The share of Americans who associate themselves with the Democratic Party has grown significantly over the past year, according to data from Gallup. The shift, which signals the party’s largest advantage since 2008, is the latest sign of backlash against Republicans and the president ahead of the midterm elections.
The latest data shows Democrats with a 10-percentage-point advantage over Republicans when voters are asked which party they identify with and when independent voters are asked which party they lean toward.
The findings come as President Trump’s approval rating has been below 40 percent for months, and as polls have found that Democrats are competitive across key Senate races in states that went heavily for Mr. Trump in past years. But shifts in party identification do not necessarily translate directly into votes, because independents, including those who lean toward a party, tend to be less politically engaged and less likely to vote.
Republicans and Democrats have seesawed between which party more Americans leaned toward over the last several years. As recently as 2024, Republicans and independents who lean toward the Republican Party held a slight edge over Democrats and Democratic-leaning independents.
The current advantage held by Democrats, though, is far wider than recent Republican leads and similar to the one the party held in 2020, when Joseph R. Biden Jr. won the presidency and the party gained a slim advantage in the House and the Senate. The high points in the last 35 years, according to Gallup, came in 2006 and 2008, when 52 percent of Americans identified as Democrats or leaned toward the party, helping Barack Obama win the White House by one of the largest margins in recent history.
Party identification shifts are cyclical, according to Jeffrey Jones, a senior editor at Gallup.
“When things are going well in the country, party identification shifts in the direction of the party in charge,” Dr. Jones said. “When things are going poorly, like they are now with an unpopular Republican president and people unhappy with the state of the nation, people are moving away from the party in charge.”
This phenomenon is what political scientists call thermostatic public opinion. Much like a home thermostat, which might click on the heat when the room gets too cold, attitudes of the U.S. public shift on a large scale when people feel that something may have gone too far.
“What we are seeing now is similar to the end of the George W. Bush administration, when he was pretty unpopular,” Dr. Jones said. “Democrats had a big lead in party identification, which was then a prelude to the 2006 and 2008 elections, which were big victories for Democrats.”
This quarter’s share of Democrats is also similar to the final quarter of the 2018 midterm cycle, when nearly 49 percent of Americans identified as Democrats. That year, the Democratic Party gained more than 40 seats in the House.
Similar data from Pew Research Center shows that this growth for Democrats is largely driven by groups that had previously shifted significantly toward Mr. Trump, including Hispanic voters, young men and young women. In 2024, young voters had a one-percentage-point Republican lean — the only time that group has favored Republicans this decade. This year, however, the Democratic advantage among the same group is 16 percentage points. Among Hispanic voters, the Democratic edge has increased by nine percentage points over the same period.
