President Vladimir Putin remains convinced that Russia will eventually wear down its smaller neighbor, causing a collapse of the Ukrainian economy and society. An elusive victory would allow him to make the case that the devastating war he unleashed nearly four years ago was worth it, after all.

Donald Trump has said he would like China's help to deal with Russia as he seeks to bring an end to the war in Ukraine.

Some of the additional sanctions the U.S. has prepared are geared toward Russia's banking sector and the infrastructure used to get oil to market, said a U.S. official and another person familiar with...