Leaning Democratic

Candidates running for seats currently held by Republicans but most at risk of swinging Democratic are evenly divided.

Tossup

A majority of Republicans in races that could go either way still support Mr. Trump. Representative Scott Garrett of New Jersey said on Saturday that Mr. Trump should step aside, but his campaign said Tuesday that he would vote for Mr. Trump anyway.

Leaning Republican

Candidates in races where Republicans have a slight advantage are split.

Likely Republican

Nearly all candidates for seats likely but not certain to remain Republican back Mr. Trump.

Position on Trump Unclear