• Upon his return to the United States, Mr. Trump will find a Republican Party in disarray.

Stephen Bannon, his former chief strategist, vowed in a Times interview that he would depose Mitch McConnell, the Senate majority leader.

Some party leaders are exploring ways to stymie a Senate candidacy in Alabama after the emergence of allegations that the Republican front-runner made sexual advances on teenagers when he was in his 30s.

Meanwhile, Republicans are racing to reshape the judiciary by installing conservative judges at a clip not seen in decades. (One nominee has never tried a case.)