In 1985, almost two-fifths of the world’s population lived in countries governed by communist parties. From the Baltics to Vietnam, and from Cuba to Ethiopia, the destinies of 1.7 billion people were in the hands of organizations formally committed to the tenets of Marxism-Leninism. Yet within a few short years, this imposing global edifice had crumbled, as one ruling party after another imploded or was driven from office. Communist parties still retain power in a handful of countries today—most notably China—but it would be hard to argue that they remain communist in any deep programmatic sense. The transformation of the People’s Republic of China into the world’s second-largest economy, overseen by a party whose ranks now contain several dozen billionaires, illustrates the depth and scale of the change that has taken place since 1989.

In the intervening years, plenty of ink has been spilled in an attempt to explain both the phenomenal worldwide rise and rapid collapse of the communist movement. These accounts have varied in tone and ideological bent, from the triumphant autopsies produced by Cold Warriors and their successors—Richard Pipes’s Communism: A History (2001), for example, and Robert Service’s Comrades (2007)—to the more measured narratives offered by left-liberal historians, such as David Priestland’s The Red Flag (2009) and Archie Brown’s The Rise and Fall of Communism (2009). Within the remnants of the communist movement, there has also been no shortage of retrospectives and reckonings. But the common focus of most of these works has been communism as a living ideology and lived experience—for its opponents, a clear and present danger, and for its adherents, still potentially a new world in the making.

A. James McAdams’s Vanguard of the Revolution has a different remit, concentrating more specifically on the communist party as an organizational form. A political scientist at Notre Dame, McAdams argues that, above and beyond the many local differences in origins and outlooks, the communist party should be understood as a single, globally recurring institution, its structures broadly replicated in a variety of places over time. Chronologically, the book takes us from communism’s inception in the mid-19th century to its much-diminished status at the end of the 20th. Geographically, we move from its German beginnings to the Russian Revolution and then outward across the rest of the globe, as if tracking the progress of a vanguard Weltgeist. Previously the author of books on 20th-century Germany, McAdams here adopts a world-spanning frame of reference, offering us a history of communism that ranges from Albania to China, Hungary to North Korea.

McAdams’s basic premise is that there is a tension running throughout the history of the communist party as a global institution: between the party as a revolutionary idea and as a political organization; between the movement’s ideals and the structures created to enact them. In McAdams’s view, this tension was apparent from the outset. Marx and Engels’s conception of the party was built around what McAdams identifies as two conflicting agendas: “One was based upon militant confrontation; the other emphasized organizational adaptation.” The same tension recurs, in one form or another, throughout the rest of the book, as the many national instantiations of the party try to keep these two components in some kind of equilibrium. But overall, the arc of the book traces the victory of organization over ideal—from The Communist Manifesto, where surprisingly little is said about the entity that will implement Marx and Engels’s program, to the ossification of the various state socialisms and their final shattering by 1991.

At the core of the communist movement’s long struggle to advance its agenda was the question of state power, and in Vanguard of the Revolution, McAdams is above all concerned with how wielding that power transformed communist parties themselves. Up until 1917, the possibility that communists would be in a position to govern an entire country had seemed remote, and for a long time, the tension that McAdams identifies between militant ideals and organizational structures remained a purely abstract concern. But the October Revolution posed the problem urgently and concretely—not just for radicals in Russia, but around the world.

Lenin’s The State and Revolution, completed a month before the Bolshevik seizure of power, famously evoked the withering away of the state apparatus, but it was unclear about what the future would hold for the party. In the early stages of Bolshevik rule, it remained an association of comrades, united in their commitment to a shared idea. But amid the maelstrom of the civil war that followed the revolution, a hardening took place—as exemplified in the crushing of the Kronstadt revolt and the ban on intra-party factions in 1921. Previously characterized by constant, fierce debates among peers, the All-Union Communist Party (Bolsheviks) became, in the mid- to late 1920s, a much larger, more bureaucratic, and more hierarchical organization; under Stalin, it was defined increasingly by its capacity to carry out directives from above. The mass purges of the mid- to late ’30s completed that transformation, literally killing off the party as it had existed prior to Stalin’s ascent.

A similar process took place, albeit in much less brutal form, in the parties that made up the Third International, or Comintern, founded in March 1919 to knit together organizations that sprang up all over the globe, from Western Europe to Southeast Asia to South America. The October Revolution made Moscow the obvious choice as the headquarters for this new revolutionary network. But that also meant the Soviet party quickly became the model that others were expected to follow, especially after the forward march of revolution in Western Europe was blocked in the early 1920s.

As the room for debate within the Bolshevik Party shrank, the Comintern’s national sections were pressured by Moscow to toe the line. Organizationally, too, they began to reproduce the Soviet party’s hierarchical tilt and, from the sectarian turn of the Comintern’s 1928 Sixth Congress on, echoed much of the dogmatism emanating from the Kremlin. But perhaps most damaging to the growth of local communist parties, the internationalist ambitions of the Comintern were increasingly subordinated to the needs of Soviet foreign policy. In 1943, as the Second World War lurched toward its endgame, the logic of that policy dictated the organization’s disbandment. To assuage the USSR’s wartime allies, Moscow called time on the world revolution.

After the Second World War, it was the Stalinized model of the party that served as the basis for what McAdams calls the “monolithic socialism” of Eastern Europe, the “people’s democracies” that led to the imposition of rigid one-party rule. McAdams surveys the fate of Eastern Europe’s communist parties in power, as well as the struggles of the parties out of power in Western Europe. As his account makes clear, in most of these cases, coercion was again used to transform existing parties, which often varied considerably in terms of both organizational structure and ideology, into Soviet-style chains of command. Though the rift between Stalin and Yugoslavia’s Josip Broz Tito was above all geopolitical, it was also, in McAdams’s view, born out of their fundamentally different approaches to party-building and the differing priority that each of them gave to ideology and organization. Yugoslavia’s expulsion from the Cominform—the Cold War–era successor to the Comintern—showed that, as far as Moscow was concerned, “dutiful states and not freewheeling parties were needed.” Tito’s maverick status was the exception that proved the rule: In the early years of the Cold War, the spread of the Stalinist model made it clear that other kinds of parties would not be permitted to emerge, imposing a leaden homogeneity on what remained, nonetheless, a living global movement.

In China, the original tension between ideals and organization persisted as a central feature of the political landscape after the Communists’ victory over the Nationalists in 1949. Many of Mao Zedong’s actions in subsequent years are depicted by McAdams as attempts to sustain the party’s vanguard ideal and thus stave off bureaucratic stasis. Mao was “driven by the conviction,” McAdams writes, “that the organizational party should be re-infused with its original ideals.” Yet Mao’s “anti-institutional approach to leadership” had other consequences that were catastrophic for the country as a whole. The voluntarism that infused the Great Leap Forward—the idea that sheer revolutionary enthusiasm would be enough to overcome the structural weaknesses of China’s economy and society—contributed centrally to its chaotic failures and the ensuing famine, in which at least 30 million people died.

With regard to the party itself, the bursts of criticism from the rank and file that Mao encouraged proved hard to rein in, most notoriously during the fevers of the Cultural Revolution in the late 1960s; in the name of avoiding Stalinist bureaucratization, the Chinese Communist Party had almost been torn apart by a tidal surge from below. Mao’s death and Deng Xiaoping’s ascent in the late 1970s presaged a shift in the character of the CCP “from a party of revolution to a party of organization,” in McAdams’s terms—a shift that accompanied and reflected a wholesale change in ideological orientation. Deng was “determined to transform the CCP into an organization that was principally suited to managing a complex economy.”

A different charismatic figure occupied center stage in revolutionary Cuba. In McAdams’s view, especially after 1961 and the announcement of Cuba’s socialist turn, Fidel Castro came to embody the revolutionary ideal, channeling it through his individual persona and frequently circumventing the party apparatus altogether with direct appeals to the populace. In the Cuban case, leader and party represent the two contrasting terms of McAdams’s analysis, rather than ideals and structure being in tension within the party itself. This is partly what makes the Cuban strand the weakest part of McAdams’s narrative. In its emphasis on Castro’s charisma, it leans on the overly familiar trope of the caudillo, framing post-revolutionary Cuban politics as a personalized struggle between Castro, the party, and the army, and thus neglects the revolution’s very real roots in the Cuban population. It is this substantial popular support, rather than the undoubted force of Castro’s personality, that really makes the Cuban case stand out within the broader landscape of communism in the Cold War era.

After Stalin’s death, ruling communist parties would make a series of attempts to renew their ideological energies and, in the process, re-establish their social legitimacy—but with only limited and temporary success. The year 1956 was a critical juncture for the world communist movement. In February, Khrushchev made his “secret speech,” setting in motion a process of de-Stalinization that was intended to return the party to its role as the embodiment of transformative ideals: The party was still, it insisted, the leading agent of revolutionary change, even in communist societies. That October, however, came the Hungarian uprising, a sudden, escalating challenge to communist rule that was suppressed by Soviet tanks after barely two weeks. These two moments encapsulated the contradiction in which communist parties were caught during Khrushchev’s Thaw: Some degree of opening was required to make the promise of ideological regeneration credible, but too much might open the way to excessive turmoil or even collapse. In the end, the see-sawing proved too much for the cadres of the Communist Party of the Soviet Union (CPSU), who in 1964 backed Khrushchev’s removal and replacement with a man more to their managerial tastes.

The Brezhnev era certainly brought an end to the Thaw and the halting liberalization of Soviet foreign policy—most graphically demonstrated with the crushing of the Prague Spring in 1968. It also brought an increased emphasis on stability, both on the world stage, through détente with the West, and within communist parties themselves: Khrushchev’s surges of enthusiasm gave way to an organizational steady state. One well-known consequence of this much greater degree of continuity was stagnation in Soviet society as a whole, reflected in slowing economic growth and declining social mobility. Communist parties began to fossilize too, becoming by the turn of the 1980s what McAdams calls a “transnational gerontocracy.” At the same time, the ideological ambitions of these parties dwindled. This was the epoch of “peaceful coexistence” with the capitalist West. It also marked the end of global class warfare. While communism remained the ultimate goal, Soviet-bloc citizens were supposed to take pride in having arrived at “developed socialism,” as Brezhnev announced in 1977: a mature industrial society that was more advanced than Lenin’s fledgling USSR had been, and more equitable than capitalism could ever be.

Yet the idea that communists should applaud this vision of systemic consolidation raised a further problem. As McAdams puts it, “Was a Leninist dictatorship needed to achieve the goals of modest economic growth and national defense?” Something similar ultimately applied to Western Europe’s communist parties—notably those in France, Italy, and Spain—which from the 1970s on sought to build coalitions with liberals and social democrats in pursuit of a democratic path to power. The Italian Communist Party’s “historic compromise” with the Christian Democrats in the mid-1970s made a certain tactical sense, but McAdams argues that it had troubling implications for the long run: “Why should one support a communist party when more moderate parties on the left could be trusted to pursue similar objectives?”

Within the overall arc of McAdams’s narrative, Gorbachev’s perestroika initially appears as a belated attempt to reinvigorate the party after its prolonged sedation under Brezhnev. But Gorbachev was beset throughout by a basic and irresolvable contradiction: how to overturn decades of bureaucratism using the very organization responsible for it in the first place? In the end, he tried to have it both ways. While insisting that the party would continue to play the leading role, in 1988 he established a parallel institution, the Congress of People’s Deputies, with multicandidate elections that opened a path to ending single-party rule. What Gorbachev seemingly did not foresee was that, in downgrading the CPSU, he was removing the linchpin that held the whole Soviet system together. Once it was gone, the USSR quickly fell apart into its separate national components.

By 1991, of course, communist parties had already tumbled from power across the rest of Eastern Europe. As the tentative market openings that many of them had initiated in the 1980s accelerated into drastic neoliberal “shock therapies” in the 1990s, many of these formerly communist parties embraced the new consensus, morphing into advocates of the same kind of free-market liberalism being purveyed by Western European social democrats at the time. North Korea’s party, for its part, shifted to a more explicitly dynastic form of rule, while in China under Jiang Zemin, the CCP reformatted itself as what McAdams calls a “servant of rapid growth.”

By the start of the new century, precious little was left of the communist party as an ideal, and the only party organizations left standing seemed to have committed themselves to entirely different principles. McAdams cites Lenin’s famous February 1922 essay, “Notes of a Publicist,” in which Lenin compares party members to mountain climbers who, in the face of impassable obstacles, must sometimes retreat in order to find another way to continue their ascent. But by the end of the 1980s, there was no longer any equivalent to the revolutionary energies of 1917 to drive the mountaineers on: “Instead of searching for a new path,” McAdams writes, “the faithful left the mountain behind.”

Vanguard of the Revolution is a very readable synthesis of the history of the communist party, from Marx and Engels’s manifesto to the collapse of the USSR. McAdams handles both the global sweep and the local details of each case he covers with an impressive assurance and levelheadedness, all while keeping his distance from the tired Cold War polemics that usually surround this subject. Given the book’s sheer geographical and temporal reach, it seems ungracious to quibble about things being omitted. Yet it is perhaps worth noting that McAdams’s predominant focus on communist parties as ruling parties somewhat skews his sample: It leaves out of the picture organizations that never attained state power and yet were politically and culturally significant. There is barely any mention, for example, of the Mexican, Chilean, or Brazilian parties—the parties of Diego Rivera, Pablo Neruda, and Luís Carlos Prestes—and there is little substantive discussion of the Communist Party of the United States of America, which of course had a notable impact on US labor history, the civil-rights struggle, and popular culture. McAdams also doesn’t mention Indonesia, which had one of the world’s largest communist parties until thousands upon thousands of its members were massacred in 1965–66 by the army and anticommunist militias—events that continue to scar Indonesian politics to this day.

Communist parties were significant even when out of power in another respect: They tended to mark the leftmost boundary of the political landscape in any given country, whether within or outside the electoral system. They thus played a role in structuring the field of political contention as a whole. During the Cold War, this was true even where communists were not numerically strong: In Central America, for example, their mere existence, or even just the rumor of it, was the pretext regional elites used to launch genocidal waves of repression.

Still, McAdams is right to focus on the problem of state power as communism’s central dilemma in the 20th century. His dual framework of the communist party as both a revolutionary ideal and an organizational form is one of the conceptual tools that enables him to structure his material. These are convenient abstractions—ideal types that mark the poles of a spectrum. But ideal types are not found in historical reality, of course, and as McAdams’s account makes clear, every actually existing communist party combined both features, in differing proportions at different times. It’s hard to imagine them not doing so: What kind of revolutionary vanguard would forswear structures that would help it realize its ideals? Conversely, what kind of revolutionary party would be all structure, lacking any ideals whatsoever (however hollow or cynically degraded these might become over time)?

Useful though it might be as a heuristic device, the categorical distinction that McAdams draws between the two tendencies ultimately elides much of the historical substance he is trying to analyze and explain. In fact, the carefully researched specifics of his narrative tell us much more than the abstract schema, showing us how communism gained adherents in a series of widely differing contexts, how those adherents then adapted and transformed the vision of a particular communist party, and how the exercise of power altered both ideas and institutions.

Gramsci famously called the Bolshevik Revolution a “revolution against Capital,” since it took place in a country where the bourgeoisie had not yet overthrown feudalism and thus involved a leap ahead of the historical sequence that Marx had envisaged. From 1917 onward, communism continued to confound those earlier assumptions, making its greatest advances not in the industrialized capitalist world but outside it, in territories subject to colonial as well as indirect domination by European powers and the United States. This in turn meant that, rather than starting from the solid platform of wealthy Western European liberal democracies, communists in these countries were in many cases forced to wage long struggles for national liberation and only then build a new system from scratch, on the ruins of the old order.

In much of the world, indeed, communism was closely interwoven with nationalist agendas. The complex interaction between internationalism and nationalism was more visibly influential than the opposition between ideals and organizations that McAdams identifies. (And here, the omission of Vietnam from the book comes to seem especially significant: It, too, has been ruled for decades by a communist party which came to power not thanks to Moscow, but to a long and arduous fight for national liberation.) On the one hand, communism as a global force drew much of its strength from its staunch anticolonialism, which allowed nationalist and internationalist projects to converge and sustain each other: The latter drove cross-border solidarity with the cause of national liberation, while the former often gained strength by placing national problems in a global frame. But on the other hand, as the history that McAdams recounts makes clear, the interests of the individual national parties often clashed with one another, as well as with the international line laid down at Comintern headquarters—not least because that line veered back and forth depending on the outcomes of power struggles in the Politburo, and in response to shifts in its view of the USSR’s interests. For instance, significant damage was done worldwide by the Comintern’s sectarian stance during its Third Period, from 1928 to ‘35, in which social-democratic forces were equated with fascists. The belated turn to the Popular Front after Hitler’s ascent to power allowed some of the lost political ground to be regained and fences with social democrats to be partially mended, but this work was then undone by the Molotov-Ribbentrop Pact of 1939.

In the view of dissident Spanish communist Fernando Claudín, these lurches themselves pointed to a deep flaw built into the Comintern from the start. In his biting two-volume analysis of 1970, La Crisis del Movimiento Comunista, Claudín noted that the Third International was designed as a single worldwide revolutionary organization precisely to avoid the fragmentation that befell the Second International in 1914, as its member parties succumbed to patriotic fervor and supported their separate countries’ war efforts. Yet the Comintern’s very centralization meant that it was too inflexible to deal with the multiplicity of national situations and experiences; and it also meant that it was liable to be swayed by the demands of the Soviet state, where the center itself was located. Over time, the interests of a single country took precedence over those of the world revolution; in the end, as Claudín puts it, the Comintern was “shipwrecked on the fact of nationality.”

Communist parties, of course, long outlived the Comintern, and their global spread reached its greatest extent after the Second World War, in particular with decolonization and the rise of Third World nationalism. But this apparent peak of communist influence coincided with the onset of the stagnation that led to these parties’ demise. Was there in fact an ironic connection between their success and their failure? Though McAdams doesn’t explicitly make this claim, it’s a question that hovers over the latter stages of the book: Were the features that made communist parties so readily replicable as organizational forms a hazard when it came to responding to the challenges of rule?

A book that traces as broad an arc as Vanguard of the Revolution is bound to contain many historical ironies. But perhaps the deepest one is not the victory of communist organizational form over ideology, but rather the fact that the solidification of party structures opened the way for a tremendous concentration of power in the hands of their leaders—subordinating vast collectives to a few key individuals. While structure may have won out over ideals, McAdams argues that it was often a highly personalized structure, enabling all kinds of crimes and abuses to occur that critically undermined the legitimacy of the parties themselves. Stalin and Mao are his prime examples here, but smaller-scale tyrannies recurred elsewhere. In effect, over the course of the book we move from abstract revolutionary ideals as formulated by Marx to their enactment by mass party organizations, and from there to their embodiment in—and sometimes betrayal by—key individuals. The personalities of these individual actors not only matter for McAdams in understanding communism’s decline; they were in many cases decisive, whether in forcing through harsh policies, prolonging their party’s grip on power, or dooming them to ill-judged courses of action.

This emphasis on the role of individuals underscores another curious feature of Vanguard of the Revolution. For a history of the communist movement, it is decidedly nonmaterialist—idealist, even—centering as it does on the emergence, growth, and steady entombment of a set of beliefs. To be sure, this is a legitimate choice of approach, and no historical account can do everything. But the relative absence of a material substrate in McAdams’s narrative—a concrete sense of communist countries’ respective positions within the global economy, or the very real structural obstacles facing any attempt to enact social change on the dramatic scale that communism intended—means that the forces shaping these parties’ policy shifts often remain somewhat opaque. Individuals and ideas were indeed crucial, as McAdams stresses. But they interacted with, and were partially formed by, constraints imposed by the capitalist order against which communists rebelled.

In the end, McAdams’s narrative remains an enigmatic ghost story: A specter takes on solid form and haunts the world, before conjuring itself out of existence. But that vanishing act was not the work of communist parties or ideas alone, nor was it the inevitable consequence of organizational entropy or ideological exhaustion. There were material factors at play, which efforts of will by themselves could not overcome. Answers to the riddle of communism’s rise and fall will therefore need to be sought not only in the varying fortunes of the movement itself, but in the stubborn resistance of the world that communism sought to change. At a moment when whole swaths of the left are debating with renewed energy and concreteness the question of alternatives to capitalism, it seems especially important to hold both sides of that picture in focus.