Previous Trump promises, threats and cajoling have failed to yield results., and the stubborn diplomatic stalemate will be hard to clear away. Meanwhile, Ukraine is losing more territory on the front line, although there is no sign of a looming collapse of its defenses.

President Trump has given an ultimatum to President Vladimir V. Putin of Russia to end the war in Ukraine or face U.S. sanctions.

Steve Witkoff, the New York real estate developer turned roving peace envoy for President Donald Trump, is heading to Russia this week for yet another round of talks with officials in Moscow with an eye towards pushing Russian President Vladimir Putin to end his years-long war against Ukraine.