President Trump met with North Korean leader Kim Jong Un on Sunday and became the first sitting U.S. president to step foot into North Korea by stepping over the demarcation line at the demilitarized zone separating the two Koreas. It was the third time Trump met Kim, and he took the opportunity to announce that U.S.-DPRK nuclear talks would resume. Kim and Trump also met privately for 50 minutes after they shook hands at the DMZ. The event on Sunday was longer than Trump had earlier indicated at the G20 meeting in Osaka, Japan. The impromptu, unconventional meeting, which was partly initiated via Twitter, was significant because it can foster trust between the two leaders. The failure to achieve an agreement in Hanoi in February was likely in part due to weak trust between the two countries. Insiders have speculated that the two sides asked too much from one another at that meeting but lacked the trust needed to facilitate a big step. It is notable that John Bolton, Trump's National Security Adviser, was not in attendance on this trip. It's also notable that South Korean President Moon Jae-in was present and appeared to help broker the meeting despite the DPRK's claim that South Korea is meddling in its affairs. Recent U.S. tensions with Iran only make personal trust between Trump and Kim more critical. The photo-op gives both Kim and Trump domestic political cover to stave off calls from hawkish advisers for a more hostile approach toward the relationship. It gives the two countries time to set up a third summit, perhaps early next year, with a reduced risk of provocations in the meantime that could throw diplomacy off track.