President Trump persuaded a conservative businessman in Nevada to drop his primary challenge to a sitting Republican senator on Friday, effectively ending a populist revolt that Stephen K. Bannon once promised would scorch establishment Republican senators from coast to coast this year.

Danny Tarkanian, a perennial candidate who had Mr. Bannon’s backing, withdrew from his race against Senator Dean Heller after a tweet from the president.

It would be great for the Republican Party of Nevada, and it’s unity if good guy Danny Tarkanian would run for Congress and Dean Heller, who is doing a really good job, could run for Senate unopposed!
— Donald J. Trump (@realDonaldTrump) March 16, 2018

At Mr. Trump’s suggestion, he said he would run for an open seat in the House instead. His decision to drop out gives a significant boost to Mr. Heller, widely considered one of the most vulnerable Republican senators on the ballot this year.