WASHINGTON -- After weeks of belligerent rhetoric, North Korea took a pause Tuesday. But where is the mercurial Kim Jong Un headed next? U.S. officials are debating whether he may want direct talks with Washington about a formal treaty to replace the 1953 armistice agreement that ended the Korean War.

The U.S. has been pursuing a dual path, threatening military conflict (semi-believably because of President Trump's verbal thunderbolts) while also urging stabilization of a denuclearized Korean Peninsula. The diplomatic trick here is simultaneously reassuring North Korea, China, South Korea and Japan that their vital interests would be protected.

This process of negotiation was hinted at Sunday by Secretary of Defense James Mattis and Secretary of State Rex Tillerson. In an op-ed for The Wall Street Journal, they warned North Korea to "take a new path toward peace, prosperity and international acceptance," or face increased isolation.

Tillerson's one, fuzzy condition for negotiations has been that Pyongyang demonstrate its seriousness by halting missile and nuclear tests. Arguably, Kim took a grudging step in that direction Tuesday, when the Korean Central News announced that he had decided to "watch a little more the foolish and stupid conduct of the Yankees," rather than carry out his threat to launch four ballistic missiles toward Guam.

Kim's problem in the escalating crisis has been that he faced a united front from the U.S. and China -- backed by South Korea, Japan and Russia. Beijing has joined Washington in calling for denuclearization and supporting additional U.N. sanctions, including a ban on new Chinese imports of North Korean coal, iron ore, and lead.

Grateful for Chinese help, the Trump administration appears to have backed off its threat to sharply limit Chinese steel exports, and to have shelved measures that could affect internet giants Alibaba and Tencent. Instead, the administration on Monday called for an investigation of China's theft of technology and trade secrets -- a serious problem for American companies but not one that requires an immediate penalty.

Trump's rhetoric has been almost as volatile as Kim's, ranging from his statement in May that he would be "honored" to meet the dictator to his warning last week of "fire and fury." But the centerline of this crisis is the same question that has vexed U.S. policy for decades -- how to deal with a rogue nation that delights in defying international norms, and now does so with nuclear weapons.

One approach to the North Korea riddle is the possibility of a peace agreement. The armistice specified that it was only a "cessation of hostilities ... until a final peaceful settlement is achieved." North Korean propaganda describes the document as "an abject declaration of surrender." But the regime understands that it's a hinge point, too. Pyongyang announced suspension of the armistice three times, in 2003, 2009 and 2013 -- only to return to observing its precepts.

As U.S. officials ponder the path of negotiation that might lead to a permanent treaty, they have signaled several basic American positions: First, the U.S. would offer assurances to North Korea that its regime wouldn't be toppled; second, it would guarantee the security of South Korea, a close U.S. ally; third, Washington would pledge not to seek any quick reunification of the Korean Peninsula, reassuring China and Japan, which fear a unified, resurgent Korea; and finally, the U.S. would express willingness to discuss the future status of its military presence in South Korea, if a peace agreement proves durable.

Tillerson has already publicly offered the first three assurances. The fourth is the most delicate, because all parties recognize that, for now, U.S. troops are an essential stabilizing force, curbing not just Pyongyang, but greater militarization in Seoul and Tokyo.

Though North Korea's nuclear-weapons program is often seen as a matter of regime survival, some U.S. officials are skeptical of that rationale. After all, conventional deterrence -- in the form of hundreds of North Korean artillery and rocket launchers that target Seoul -- has checked any attack on Pyongyang for three generations of Kims.

B.R. Myers, whose 2010 book "The Cleanest Race" is being closely read by U.S. officials, argues that North Korea isn't really a communist regime, but one propelled by right-wing talk of Korean racial purity. Its goal may be the "victory" and unification it failed to achieve in 1953.

A Chinese-American partnership has helped move this crisis back from the brink. But that's a sideshow for Kim. The encounter he may truly want is with the deal-maker himself, Donald Trump. For that showdown, you could sell tickets.

(c) 2017, Washington Post Writers Group