Pope Francis’ address to the United Nations on Friday engaged robustly with world politics. He presented a carefully reasoned, systematic philosophy of peace, conflict, and the environment, driven by a few central principles such as multilateralism, reasoned faith, and care for human life. This philosophy drove him to support the Iran deal and to take the stance of a climate hawk. On virtually every issue, he came down against the key talking points of the Republican presidential candidates, who had counted on culturally conservative Catholics to support their belligerence toward Iran and their climate-change denial.

The Republican candidates universally proclaim themselves “pro-life,” as does the pope. But if life is sacrosanct, then surely war should be avoided, too, and assassinations and capital punishment should be banned. With the exception of Rand Paul, the GOP field for the most part strongly supported George W. Bush’s unilateral and unprovoked attack on Iraq, which has left hundreds of thousands dead, millions displaced, and the region in turmoil. It is hard not to hear a critique of that war of aggression in the pope’s pronouncement that “hard evidence is not lacking of the negative effects of military and political interventions which are not coordinated between members of the international community.”

Worse, the Republican candidates seem positively eager for another such war, this time with Iran. Ted Cruz, even as Francis was speaking at the UN, was rattling sabers and announcing his intention to murder Iran’s Ayatollah Ali Khamenei. Even the more soft-spoken Jeb Bush spoke of wanting a “better deal” with Iran, and then went on revealingly to say that the United States had gotten a “pretty good deal” with regard to Iraq’s dictator, Saddam Hussein (executed by US-backed Shiites). Pope Francis is not even in the same universe with these candidates except on the narrow issue of abortion, which most of the Republicans only oppose to attract Catholic and evangelical votes (this point is obvious in the cases of Donald Trump and Carly Fiorina).

Pope Francis framed his support for the UN Security Council’s Joint Comprehensive Plan of Action with Iran precisely in anti-war terms. He grounded the search for peace, moreover, in the rule of law. The pontiff observed, “there is a need to ensure the uncontested rule of law and tireless recourse to negotiation, mediation and arbitration, as proposed by the Charter of the United Nations, which constitutes truly a fundamental juridical norm.”

The pontiff praised the multilateral, law-based activities of the United Nations, which he called “necessary” for all its shortcomings, insisting, “All these achievements are lights which help to dispel the darkness of the disorder caused by unrestrained ambitions and collective forms of selfishness” [emphasis mine]. Unrestrained ambitions and collective selfishness have been amply on display in the circus of the US political campaign season. Donald Trump has whipped up a dangerous anti-immigrant fervor, and the candidates are outbidding each other in criticisms of President Obama for not having been more warlike. All of the Republican candidates have pledged to undo the careful UN Security Council negotiations that led to the Iran deal.

The complete disregard in the Republican Party in particular, and in American politics in general, for the rule of law when matters of security are allegedly at stake is startling when considered against the European Union, for instance. The enthusiasm in Washington for George W. Bush’s Iraq War was an incredible affront to this principle, since Iraq had not attacked the United States and no Security Council resolution authorized the use of force. This severe violation of the basic norms of the UN Charter was not even an issue inside the Beltway.

Pope Francis sees war and environmental degradation as intertwined. That is, both menace human life and the web of nature in which it flourishes. Indeed, war always itself damages the environment in addition to piling up human bodies. He said: “War is the negation of all rights and a dramatic assault on the environment. If we want true integral human development for all, we must work tirelessly to avoid war between nations and between peoples.”

The worst kind of war of all, both for the environment (can you say, “nuclear winter”?) and for human beings is war pursued with atomic bombs. Pope Francis condemned nuclear proliferation. But he went beyond this warning to critiquing the doctrine of “mutual assured destruction,” which some political scientists have argued maintains peace among nuclear-armed states. He complained that any system of ethics founded on this strategy is “self-contradictory and an affront to the entire framework of the United Nations, which would end up as ‘nations united by fear and distrust.’”

This careful chain of reasoning led the Pope to his approbation of the JCPOA with Iran, saying, “The recent agreement reached on the nuclear question in a sensitive region of Asia and the Middle East is proof of the potential of political good will and of law, exercised with sincerity, patience and constancy.” Unlike the Republicans, who want to undo the deal immediately, the Pope said, “I express my hope that this agreement will be lasting and efficacious, and bring forth the desired fruits with the cooperation of all the parties involved.” He sees the Iran deal as exemplary of multilateralism (it was negotiated by all the permanent members of the Security Council as well as Germany, which unofficially represented the European Union). He sees it as a product of respect for the rule of law. He sees it as an important step in the struggle against proliferation. He sees it as an alternative to war and thus as an affirmation of life.

These values—of international law, working closely with allies, and preferring careful and effective diplomacy to unilateral, aggressive war—are virtually the opposite of the ones we usually hear from the GOP field (again, Rand Paul and to some extent John Kasich are exceptions). Pope Francis was not speaking ex cathedra or on behalf of the church, or laying down church doctrine, so many right-wing US Catholics will ignore his political stances. But by his consistency in affirming the supremacy of life in all spheres—including diplomacy, climate change, and taking care of refugees and the poor—he has modeled a profound critique of Republicans’ hypocrisy in supporting war, Scrooge-like policies toward the disadvantaged, and the wrecking of the UN Security Council’s Iran accord, while proclaiming themselves pro-life on one narrow issue.