President Trump and North Korean leader Kim Jong Un shake hands before their meeting in Hanoi on Thursday. (AP/AP)
Contributing columnist

For years now, President Trump and his administration have been advancing a fundamentally illogical contradiction in their nuclear diplomacy toward Iran and North Korea. In both cases, the stated public goal of Trump administration policy is the same: denuclearization. Yet the strategies for achieving this worthwhile U.S. national security objective are diametrically opposed depending on the country in question.

In its efforts to block the nuclear program of Iran (which hasn’t even produced a workable weapon yet, as far as we know), the Trump administration has pursued an aggressive strategy of pressure and confrontation. There are even signals that some in the administration believe that the ultimate aim must be regime change. To achieve denuclearization in North Korea, however, Trump has pursued a strategy of intense and focused engagement. No U.S. president had ever met with a North Korean dictator; Trump has wined and dined with his “friend” Kim Jong Un twice. To date, both strategies have achieved little.

The administration’s efforts to explain the divergence in its approaches make little sense. In negotiating the Iran nuclear deal, the Obama administration, we are told, took many other contentious issues in U.S.-Iranian relations off the table. The Trump administration, therefore, had to withdraw from this allegedly flawed multilateral agreement — formally known as the Joint Comprehensive Plan of Action (JCPOA) — to better pursue our other security objectives, such as stopping Tehran from supporting terrorist organizations abroad, threatening our allies in the Middle East, or maintaining theocratic oppression at home. At least rhetorically, Iran is one of the few counties in the world in which Trump and his team seem committed to promoting democracy and human rights.

Trump and his foreign policy advisers have good reasons to focus on these nonnuclear sources of tension in U.S.-Iranian relations. But they have never adequately explained why pulling out of the JCPOA helps the United States to make progress on these other issues. Analogies from the Cold War suggest that this kind of linkage of unrelated issues rarely works. Even as President Ronald Reagan and his administration pursued arms control with the Soviet Union in one lane, they also pushed for the rollback of communist regimes in the developing world and support for human rights inside the Soviet Union and Eastern Europe, regardless of bilateral negotiations with the Kremlin over nuclear weapons. To date, there is little evidence that the Trump strategy to roll back Iranian terrorist operations and weaken theocracy while at the same time thwarting Iran’s nuclear program is working. Instead, the Trump strategy so far has isolated the United States even from our European allies.

Trump’s maximum pressure approach toward Iran looks especially illogical when juxtaposed with his charm offensive toward Kim. The president’s strategy — which I cautiously support — is to nurture a direct, personal relationship between the two heads of state as a means toward denuclearization. As far as we know, this approach has achieved little so far (except for legitimizing Kim). But if this policy eventually gains momentum, it will require Trump to engage in the same set of trade-offs with North Korea that he has lambasted in the case of Obama’s Iran policy. To get a nuclear deal, the United States will have to lift sanctions and provide economic inducements to a ruthless dictator. And regime change will not be part of the agenda. Trump has spoken glowingly about how Kim has the potential to make North Korea an economic powerhouse, which will implicitly strengthen his hold on power.

There is an alternative hypothesis about Trump’s nonproliferation strategies that reconciles these seemingly contradictory policies. Perhaps complete and verifiable denuclearization is not the goal in either case. In Iran, it may be that the real objective is regime change, including the option of U.S. military action. (Such a strategy is very unlikely to work, but that’s a discussion for another day.) If you are pursuing a policy of regime change, you have no interest in engagement or diplomacy; just the opposite, since you aim to vilify the autocrats in power to justify overthrowing them. In North Korea, it could be that the goal is not complete denuclearization, but an outcome that allows Kim to maintain part of his nuclear arsenal while perhaps dismantling his ICBM program to reduce the direct threat to U.S. national security. This lesser goal could help to explain why Trump is so oddly accommodating toward North Korea, and so unwilling to increase pressure, even when Kim has signaled no credible commitment to complete denuclearization.

In both scenarios, though, time is not on Trump’s side. Here’s my nightmare scenario. In summer 2020, Trump is trailing in the polls by 10 to 15 percentage points. To save his bid for reelection or, if a one-term president, secure a tangible achievement for his foreign policy legacy, Trump might resort to radical solutions in nuclear diplomacy — war with Iran and/or an agreement with North Korea well short of complete denuclearization. As a proud disrupter, Trump is exactly the kind of president who just might be tempted by these unorthodox, radical outcomes. Accordingly, Congress, the American media, the foreign policy expert community and the general public must do all that they can to reduce the likelihood of either of these scenarios unfolding.

Read more:

David Ignatius: It made sense for Trump to walk away in Hanoi

Fareed Zakaria: America’s bitter polarization exacts a price on its credibility abroad

The Post’s View: The Hanoi summit failure exposes Trump’s weak diplomacy

Henry Olsen: No, the North Korea summit was not a loss for Trump

Dana Milbank: Why does Trump fall in love with bad men?