President Donald Trump, on the 2024 campaign trail, repeatedly promised voters he personally could end the Russia-Ukraine war on his first day in office -- or even before.

President Trump appears to have backed off joining a European push for new sanctions on Russia, seemingly eager to move on to doing business deals with it.

If Mr. Trump keeps the two issues intertwined, it could confine Russia to an economic purgatory, with little immediate chance of getting relief from Western sanctions or of bringing the foreign inves...