But the United States appears unlikely to re-enter talks with North Korea anytime soon, although Kerry, now secretary of state, has kept that possibility open if Pyongyang takes concrete steps to show it is serious about denuclearization.
For one thing, the administration has its hands full. On foreign policy, it is embroiled in diplomacy on Iran's nuclear program and the Syrian civil war—adopting moderate stances that have rankled some of its allies in the Mideast. It's also fending off anger from allies in the West, such as Germany, France and Spain over spying allegations.
On the domestic front, President Barack Obama has lurched from a budget-standoff that sparked a 16-day partial government shutdown and brought the U.S. within a whisker of debt default, to damage limitation over the botched roll-out of his landmark health care policy.
That leaves little time, or perhaps political appetite, to chance the administration's arm at another round of diplomacy with Kim Jong Un, whose government spoiled the last round in spring 2012 by launching a rocket into space—what the U.S. regarded as a test of ballistic missile technology that could potentially threaten America.
Then this February, the North conducted an atomic test and later threatened pre-emptive nuclear strikes on the U.S. when it led the international effort to tighten sanctions.