WASHINGTON (AP) — An enigmatic North Korean leader takes a secretive train trip to China to affirm fraternal ties and declare a commitment to denuclearization.

It sounds like Kim Jong Un's visit this week, but his father and predecessor Kim Jong Il made similar declarations on a trip to Beijing, months before he died in 2011. Yet North Korea's nuclear weapons development only speeded up.

President Donald Trump expressed optimism Wednesday after the younger Kim's meeting with Chinese President Xi Jinping, saying there's "a good chance" that Kim will "do what is right for his people and for huma...