President Donald Trump’s deadline for Russia to end its war in Ukraine or suffer severe economic punishment expires Friday, but it’s unclear how he plans to proceed amid new efforts toward a summit with Vladimir Putin and delicate trade negotiations with China.

Russian forces have the advantage on the battlefield, so a decision by Mr. Putin to settle rather than try to conquer more of Ukraine should be seen as a concession in itself, said Feodor Voitolovsky, director of the Institute of World Economy and International Relations, a Russian government-funded research group.