The appearance of a Democrat lauding the policies of an administration that his party is claiming has made life harder and more expensive for Americans was a stunning turn and a boon for Mr. Trump, coming just weeks before crucial midterm elections in which Republicans are battling to defend their slim congressional majorities.
And it was a setback for Democrats’ efforts to focus the final crucial weeks of the midterm campaign on the president, whose approval ratings are sagging, and his unpopular policies. Mr. Fetterman’s surprise virtual appearance, which the people familiar with his plans disclosed on the condition of anonymity because it had yet to be announced, instead promised to spotlight divisions among Democrats.
It also came amid speculation that Mr. Fetterman could in the future switch parties, a move he has said he would “never” make but has appeared more likely as his breaks with his own party have become more frequent and bitter.