After posing for photos with North Korea’s leader, Kim Jong-un, and then recrossing to South Korea for an hourlong bilateral meeting — marked by a chaotic scrum between Mr. Kim’s security team and Western reporters — Mr. Trump announced that the two leaders would restart stalled nuclear talks. He also said he would invite Mr. Kim to visit the White House.

How it happened: Barely 24 hours earlier, Mr. Trump had made a surprise announcement on Twitter, saying he would meet Mr. Kim at the heavily fortified Demilitarized Zone “just to shake his hand and say Hello.”

That tweet morphed into what is widely seen as a symbolic moment of reconciliation.

Analysis: For Mr. Trump, the moment provides a handy storyline for his re-election campaign. And, while many experts are convinced that Mr. Kim will never give up his nuclear arsenal, this brief meeting may boost the North Korean leader’s standing at home and motivate him to reach an agreement.

The U.S. and China call a trade truce. For now.

At the G20 summit in Osaka, Japan, President Trump and President Xi Jinping agreed to resume trade talks, averting for the moment an escalation of their multibillion-dollar tariff war.