With Republicans seen as less likely to hold their majority in the House, the party is focusing more on the battle for the Senate, where it is vastly outspending Democrats on ads.

© The New York Times

Democratic Senate candidates have generally out-raised Republicans, but are struggling to match outside spending from Trump-affiliated groups.

© Haiyun Jiang/The New York Times

The president yanked his endorsement of Representative Jeff Hurd of Colorado, imperiling Republicans’ chances of holding onto his seat as they brace for midterm losses.

© Kenny Holston/The New York Times