If the dream of a peaceful, prosperous, denuclearized Korean peninsula is to become a reality, North Korea’s leaders, who have deeply distrusted the United States for decades, will have to believe that Trump (and whoever succeeds him) will honor the grand bargain that Biegun has in mind—a long shot that Friday’s move may make longer. And Trump himself will have to prove as accomplished a deal maker as a deal breaker .

The Trump administration’s stance so far on nuclear-arms-control and nuclear-nonproliferation agreements has been “repeal and don’t replace,” Kingston Reif of the Arms Control Association told me in October, when the president first hinted that he would ditch the INF Treaty.

On Friday, Russia and the United States blamed each other for the demise of the second-to-last treaty restricting the world’s two largest nuclear arsenals.

Russian Deputy Foreign Minister Sergei Ryabkov asserted that U.S. officials have embarked on a new arms race, while a senior Trump administration official, speaking on the condition of anonymity, declared, “If there is to be an arms race, it is Russia’s actions that have undermined the global security architecture and have undermined this particular arms-control agreement.”

The American official has a point. Washington has, since the Obama administration, been accusing Moscow of violating the INF Treaty by developing and fielding a banned cruise-missile system, to no effect. That’s why NATO has backed the Trump administration’s notification of withdrawal from the pact, which grants Russia six months to come back into compliance before the U.S. exit is official. In calling out Russia’s breach of the INF Treaty, the administration could argue that it is sending a message to Pyongyang that the United States won’t stay in a deal it feels the other party is betraying.

But it’s also true that, as Ryabkov suggested, the Trump administration has shown contempt for international arms-control and nuclear-nonproliferation agreements. A number of the president’s advisers—most prominently, National-Security Adviser John Bolton —“don’t like negotiated arms control. They see it as abridging U.S. sovereignty” and constraining freedom of action, Richard Burt, who helped negotiate the INF Treaty during Ronald Reagan’s administration, told me last fall.

Trump has justified his withdrawal from the Iran nuclear deal and the INF Treaty as the necessary first step to making better deals. With Iran, for example, the administration envisions a deal that would prohibit not only Iran’s nuclear pursuits, but also its ballistic-missile program and regional behavior. With the INF Treaty, the president has said he wants both Russia and China, which possesses hundreds of shorter-range nuclear-capable missiles but is not party to the treaty, to “come to us and they say, ‘Let’s really get smart and let’s none of us develop those weapons.’ ”

In neither case, though, has that ideal deal yet materialized.

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