For decades, progressives and Democrats have searched in vain for a wedge issue to call their own, something that could match the success Republicans have had in using race, abortion and homosexuality to split the electorate. Yet unable even to leverage environmental catastrophe, drastic economic inequality and near global financial collapse to their advantage, Democrats have instead mastered trimming and triangulating, accepting much of the conservative agenda while promising to implement it more effectively. But if Democrats could overcome their shortsightedness and embrace immigrants’ rights—as passionately as Republicans mobilize around tax cuts, fetuses and war—they may find the holy grail they’ve been looking for, one with the power to transform domestic and foreign policy. Here are nine reasons immigration reform, especially legislation that will grant citizenship to the millions of undocumented Latinos, is a progressive game changer:

1. Immigration reform ends the Southern strategy. For more than four decades, the conservative movement’s base has been the segregationist South, subsidized by an archaic Electoral College system that grants disproportionate power to majority white voters in Southern states. The enfranchisement of millions of undocumented Latino workers, combined with the votes of Latino citizens, would change that, turning red states purple and purple states blue. Almost 10 million Latinos voted in 2008, 7.4 percent of the total, and a large majority voted for Barack Obama. Analysts believe Latinos were responsible for giving the president larger than expected victories in key swing states like Nevada, Colorado and New Mexico. They helped him squeak out a win in North Carolina and forced John McCain to defend Republican strongholds like Georgia. Then there are Texas’s thirty-four electoral votes, without which the GOP’s chances of winning national office collapse. Latinos make up more than 20 percent of registered voters there, with their turnout increasing 30 percent between 2000 and 2008. Even direr for Republicans, in ten years Latinos are expected to be the state’s largest ethnic group, surpassing whites. By 2040 they will be an absolute majority.

Every election cycle, the number of registered Latinos, as well as actual voters, increases. They are trending Democratic—67 percent voted for Obama, up from 59 percent for Kerry in 2004. Democratic support for reform would ensure that this trend continues. Seventy-eight percent of Latino voters identified immigration as important to them and their families; 62 percent say they know someone who is undocumented. Forget futile efforts to abolish the Electoral College; the best way to wrench the dead hand of the Confederacy off the throat of the political system is to enfranchise Latinos.

2. It wins back the Catholic Church to social justice. Catholics, mostly white ethnic working-class migrants, were stalwarts of the New Deal coalition. But they began to peel away in 1980, with the backlash to Roe v. Wade. In 2004 the future pope Benedict XVI, then the head of the Vatican’s Congregation for the Doctrine of the Faith, helped Karl Rove execute his "Catholic strategy," urging priests to deny communion to politicians who support abortion (i.e., Kerry). The combined Catholic vote roughly split that year, with white Catholics breaking for Bush and Latinos for Kerry.

But immigration reform now has the potential to trump abortion as a wedge issue. Latinos, who make up one-third of its membership, are the best shot the US Catholic Church has of remaining viable. And though the church has become increasingly conservative over the past two decades, when it comes to immigration its social justice ethos is still intact. Priests and congregations have been vocal in opposing Arizona’s SB 1070, and central in providing safe havens and basic services to migrants. Even the Vatican’s recently appointed conservative archbishop of Los Angeles, Mexican-born José Gómez, a member of Opus Dei, has stated that in "Catholic teaching, the right to migrate is among the most basic human rights. It’s very close to the right to life. Why? Because God has created the good things of this world to be shared by all men and women—not just a privileged few."

3. It slows the inclusion of Latino evangelicals into the religious right. "Woe to the legislators of infamous laws, to those who issue tyrannical decrees, who refuse justice to the unfortunate and cheat the poor among my people of their rights…. What will you do on the day of punishment, when, from afar off, destruction comes? To whom will you run for help?" This bit of fire and brimstone from the Book of Isaiah was recently cited by the National Hispanic Christian Leadership Conference, the nation’s largest Hispanic Christian organization, to condemn SB 1070.

The religious right is actively courting Latinos, who make up a small but growing percentage of evangelicals. But the poor, precarious situation of many congregations limits their inclusion in conservative politics. Like their Catholic counterparts, Protestant pastors spend much of their frontline ministry helping undocumented workers. After a recent meeting with Obama, Pentecostal pastor Samuel Rodriguez, who has been wooed by 2012 Republican hopefuls, said that the president’s position is "99.9 percent" in line with evangelical doctrine. Likewise, Latino Mormons are demanding that leaders of the Mormon church take a stand against the Arizona law, even while many conservative white Mormons—like State Senator Russell Pearce, who sponsored SB 1070, and Utah Representative Stephen Sandstrom, who hopes to implement a similar law in Utah—are on the other side of the issue, insisting that church law demands enforcing immigration laws.

4. It is lose-lose for Republicans. Put immigration reform on the docket before the midterm elections and watch Republicans squirm. If they support it, they enrage their Tea Party base. If they oppose it, they keep the Tea Party and might win, even big, in November, but will so anger the more electorally important Latinos that not even Spanish-speaking Jeb Bush, with help from his Mexican-born wife, will be able to win them back. As Ruy Teixeira notes, the "GOP dilemma" is that the Tea Party might help Republicans win in November but that short-term gain will be a long-term loss, a death embrace with a rump political movement that "concentrates in one place the most extreme and reactionary views." By pushing immigration reform before the midterm elections, the Democrats would magnify this dilemma. Let South Carolina’s GOP gubernatorial candidate Nikki Haley explain to Latino voters why she calls for stepped-up deportation, opposes amnesty and applauds SB 1070 in the name of "states’ rights." Immigration reform could also short-circuit any attempt to restore the Bush dynasty through Jeb, who has spoken out against the Arizona law and in favor of reform.

5. It splits the conservative coalition in other ways. A fight over immigrants’ rights drives a wedge between business Republicans and the GOP’s "no-amnesty," know-nothing wing. Last year, the powerful National Association of Evangelicals issued a statement calling for comprehensive, dignified reform, which was strongly criticized by the conservative Institute on Religion and Democracy. And the "purity" of Ron and Rand Paul’s libertarianism—as the mainstream media never cease to describe what is largely a rebranding of paleoconservatism—seems a lot less pure when they get started talking about "electronic fences," "helicopter stations" and "making English the official language of all documents and contracts." So much for the right to engage in economic transactions as one wishes.

6. It revitalizes the union movement. Latino immigrants have already helped turn Los Angeles, Las Vegas and other cities into union towns. They’ve often done so against great odds and with impressive courage, since many undocumented union workers are not fully covered by the National Labor Relations Act. Imagine what they could do if they were protected by labor law. Despite all the Republican talk about Latinos being natural conservatives, committed to family, religion and hard work, most reject the extreme economic individualism that is the bedrock of the GOP. They come from countries where democracy means social democracy, including workers’ rights, welfare and economic justice.

7. It dilutes the power of Florida Cubans. Since the 1959 Cuban Revolution, Cuban exiles have had a toxic effect on US domestic and foreign policy. They have repeatedly helped deliver Florida’s large number of electoral votes to Republicans and in 2000 served as the shock troops for the infamous "Brooks Brothers Riot," which shut down Dade County’s recount of its disputed presidential ballot, a critical event that helped hand the election to Bush. Beyond forcing Washington to keep up its pointless embargo of Cuba—which handicaps US diplomacy in the rest of Latin America—they have backed a hardline foreign policy, supporting Ronald Reagan’s patronage of death squads in Central America and last year’s coup in Honduras. Their power is on the wane; in 2008 other Florida Latinos helped deliver the state to Obama, overriding the Miami Cuban-American vote, which went for McCain. But candidate Obama still felt compelled to genuflect before them, traveling to Miami to criticize Bush from the right for losing Latin America to leftist "demagogues." Legislating a way to citizenship for Latino immigrants would dampen Florida Cubans’ ability to influence foreign policy, as well as change the terms of the debate: even Cuban-Americans are in favor of immigration reform.

8. It helps America’s cities. I lived in Durham, North Carolina, for a few years, and for all the romance of Southern porch culture, it was mostly Latinos, nearly all of them undocumented laborers from Mexico and Central America, who were outside, facing the street, talking, listening to music, raising families. The city’s more settled residents were inside with their air-conditioners and TVs. Throughout the United States, Latinos are re-energizing neighborhoods and populating downtowns, opening stores and pumping money into established small businesses. Not too long ago cities were rearguards of a progressive ethos in retreat. Today, with the help of Latinos, one of the fastest growing urban demographics, they are again vital hubs of social democracy. Google the words "Latinos," "cities" and "revitalize" and you will be led to any number of stories about how stressed city centers in Detroit, Dallas, Memphis, Newark and the Hudson Valley are being rescued by Latinos. No wonder the right hates them.

9. It is the morally right thing to do. And as a result, it is strategically smart. Progressives need not just wedge issues but driving righteousness, and the heart-rending plight of more than 10 million vulnerable residents who are denied basic human rights and hunted by random raids, their families split apart, is as morally urgent an issue as the civil rights movement was in its heyday. Considering the role Latinos would play in burying, once and for all, the Southern strategy, the issue needs to be understood as essential in finally achieving the promise of the original civil rights movement. With one eye on November’s midterm elections and another on polls showing support for Arizona’s SB 1070, many Democrats are reverting to hedging. It’s a "toxic subject," says Democratic Governor Phil Bredesen of Tennessee. For all the reasons above—plus the fact that many Latinos might just wash their hands of the Democrats if betrayed—that temerity itself is toxic. And considering Democrats’ perpetual minority status in Tennessee, if I were a Democrat there, I’d want as liberalized an immigration policy as possible.