Dropping support for the Democrats is concentrated among current and former Democratic voters. In YouGov’s tracking, Democrats’ favorable ratings are down since late October by four points among Republicans, five points among independents, and 14 points among Democrats. At the same time, the share of respondents who say they’re Democrats has dropped from 37.8 to 30.5. Combine the declining share of Democrats and increased unhappiness among the remaining Democrats, and you’ve explained most of the party’s 11.7-point decline in favorability among all adults.

The silver lining for Democrats: Some, maybe most, of the unhappy Democratic voters are unhappy because they think their party isn’t doing enough to stop President Trump. If that’s their motivation, they will still probably show up to vote against Republicans in 2026. Whether that also describes a large chunk of the voters who no longer consider themselves Democrats is doubtless a question that the party’s data professionals are trying to figure out.