1. “There’s a very substantial chance that it won’t work out.”

President Trump cast doubt on his planned meeting next month with North Korea’s leader, Kim Jong-un, in Singapore. His comments came as he met with President Moon Jae-in of South Korea at the White House, above.

Mr. Moon has acted as a go-between in the proposed talks, and South Korea had insisted on Monday that there was a “99.9 percent” chance that the meeting would be held.

If the North maintains its nuclear arsenal, can Mr. Trump still claim diplomatic victory? It will depend on how he redefines success — and if he meets with Mr. Kim, our correspondent noted.