Still, a process has begun. As almost all commentators have noted, it will be long and difficult. It will have to overcome hurdles of geopolitics, decades-long hostility, trust, verification, personality and intra-alliance relations, just to name a few.

               There’s another, less discussed, obstacle ahead: the excessive partisanship that has infected so much of America’s foreign policy debate. If President Trump and the Congress don’t approach this nascent process with a new-found spirit of bipartisanship, success will be far less likely.

               For the importance and value of a bipartisan approach to denuclearization, look no farther than the Nunn-Lugar Cooperative Threat Reduction program. It rid three countries—Belarus, Kazakhstan and Ukraine—of all their nuclear weapons, and slashed the huge Soviet arsenal in Russia. It was conceived by a Republican, Sen. Lugar, and a Democrat, Sen. Sam Nunn of Georgia, at a time when the collapsing Soviet Union was still seen by many in both parties as a existential threat to the United States. As sensible as it may seem in retrospect, at the time the idea of spending millions to help our long-time foe was highly controversial.

               Sens. Lugar and Nunn, in a recent Washington Post op-ed and an NPR interview, have proposed applying the lessons learned from the Nunn-Lugar program to North Korea in some future program to dismantle or render inoperable that country’s nuclear bombs, missiles and uranium and plutonium facilities. An authoritative Stanford University roadmap for possible North Korean denuclearization also noted that Nunn-Lugar could serve as a model for North Korea.

               But the political lessons from Nunn-Lugar could be a model for the administration and Congress, too.  Because the two Senators approached the problem in a bipartisan manner, wary colleagues on either side of the aisle could see that this unprecedented proposal was not being made for partisan gain. And because the two were respected experts in foreign policy and military affairs, with reputations for fair dealing, they were able to convince many of the skeptics, both in Congress and the public, that this was not a handout, but an investment in our own national security.  As a result of their strenuous efforts, the legislation was passed 86-8 in the Senate and by acclamation in the House. President George H.W. Bush signed it on Dec. 12, 1991, just four days after the Soviet Union officially began to break up.

               This solid, bipartisan backing was an important factor in the subsequent success of Nunn-Lugar. Too often in recent years, many important foreign policy votes have not even been taken because Congress was afraid of partisan backlash. And the few foreign policy measures that passed did so with narrow, largely partisan, majorities. This sows doubt about our nation’s resolve, and threatens future support. The strong Nunn-Lugar vote showed the former Soviet states and our allies that we were committed to the program and in it for the long haul.  That’s a key lesson for the administration, which has vowed to bring any North Korea deal to Congress for approval. A bipartisan approach at the beginning of the negotiations is much more likely to yield a strong bipartisan vote at the end.

               Another important lesson from Nunn-Lugar is that its strong bipartisan nature helped it endure for many years. Within a year Bush was succeeded by Democrat Bill Clinton, and soon after that Congress experienced its own political upheaval. Despite new personalities, shifting priorities and budgetary battles, Nunn-Lugar stayed the course because both parties were invested in it. It was not seen as a Democratic or Republican program, so it was spared much of the increasingly partisan rancor that engulfed Washington. Any North Korea agreement is likely to require many years to complete. Strong bipartisan backing would make it more likely to last long enough to complete the job.

               But to get bipartisan support, the President will have to genuinely engage with Congress, including both parties.  Up to this point, he has treated the North Korea problem as an issue that depends exclusively on his personal negotiating instincts and ability to establish a rapport with Kim Jong Un.  But the limits of this approach were vividly underscored by his jaw-dropping declarations that Kim is loved by his people and that "there is no longer a nuclear threat from North Korea."  The hard work is in front of us, not behind us.  Bringing Congress along is vital to its success. He will need Congress to approve many of the anticipated steps along the way: a possible peace treaty to end the Korean War will require a two-thirds vote by the Senate; if the president, as he has suggested, agrees to an aid package for North Korea, Congress will have to approve the funds; and any final deal is likely to require extensive Congressional debate.  Failure to consult Congress, as he has done in imposing steel and aluminum tariffs, will deepen Congressional skepticism. 

                Sen. Lugar has often noted the great success that President Reagan had when he endorsed the formation of a bipartisan Senate Arms Control Observer Group and gave it an official role in arms control negotiations: they were to “consult and advise” the American negotiating teams and to regularly report back to the Senate on the progress of the talks. Sen. Lugar, who was an original member, has said the Observer Group “was tremendously important in forming a consensus.” The administration was able to secure overwhelming bipartisan support for two important and potentially controversial treaties, the Intermediate Nuclear Forces treaty and the first START treaty. President Trump should consider a similar model.

               Another reason for engaging Capitol Hill is that Congressional backing actually strengthens Trump’s hand at the bargaining table.  Through robust engagement and consultation with Congress along the way, Trump will be able to say, ‘Congress demands X’ or ‘Congress won’t accept Y,’ and the other side will know he’s not bluffing. Pyongyang will also have confidence that Trump can deliver on his promises if he has Congressional approval in advance.

               At this point, it’s unclear whether the president will involve Congress closely in the negotiating process. Congress seems willing to listen. Republicans, who reacted with partisan fury when Democratic presidential candidate Barack Obama said he was willing to meet with dictators like North Korea’s, have made an about-face and lavished praise on President Trump for meeting with Kim. Democrats, while noting the apparent partisan double standard and questioning the substance of the agreement, have refrained from harsh partisan attacks against the meeting. Senate Democratic leader Chuck Schumer said, “We remain supportive of American diplomatic efforts.” President Trump should take that as an invitation to build bipartisan backing for the North Korea process. As Nunn-Lugar showed, bipartisanship can yield great results.