Early voting is underway in half the country, and the numbers are flashing warning signs for Republicans fighting to preserve their House and Senate majorities. Across key battlegrounds, Democrats are casting more ballots while the GOP struggles to get its own voters to participate.

Registered Democrats account for 53% of early and mail ballots cast across 10 Senate battlegrounds, according to NBC News data. Registered Republicans account for only 34%, and Republicans have not outpaced Democrats in any of those states, which range from Kansas to Maine.

Republican voting was also running behind its pace from the same stage of the 2022 midterm cycle. As of last Wednesday, GOP ballots trailed their comparable 2022 total in 10 of the 12 states with party registration data and significant ballot activity, according to TargetSmart senior adviser Tom Bonier.

Democratic voting was likewise behind the 2022 pace in nine of those states, which Bonier attributed to declining use of mail voting. Even so, Democrats had cast more ballots than Republicans in 10 states.

That imbalance could be especially damaging because polls show independent voters moving toward Democrats. A substantial decline in Republican participation could therefore leave GOP candidates facing serious trouble across the map.

Election analyst Zachary Donnini said the voting data broadly matches what likely voter polling has suggested. He pointed to Democratic strength in several states and multiple indicators showing a wider enthusiasm advantage.

“So far, the Early Vote data I’ve seen has been broadly consistent with what those likely voter polls are suggesting. Across the board, the people showing up to vote in person appear to be disproportionately Democratic,” Donnini wrote on X.

“We first saw it in Virginia and Ohio, and now this week’s early voting in Georgia and North Carolina has been particularly concerning for Republicans. Mail ballot return rates in New Jersey and Arizona tell a similar story. Nearly every measure of enthusiasm I’ve seen, both in surveys and in early voting, currently favors Democrats.”

The state numbers offer Republicans little comfort. In North Carolina, the Republican share of the early voting electorate is down 9 percentage points compared with the same stage of the 2022 election, according to The New York Times.

Iowa presents another glaring problem for the GOP. Democrats are seeking to capture the state’s open Senate seat, currently held by Republicans, and they lead in ballots already cast by 54% to 30%.

That represents a sharp shift from the comparable moment in 2022. At that point, Democrats accounted for 48% of the early vote while Republicans represented 39%.

Early voting data still comes with important limitations. Party registration does not guarantee that a voter supported that party’s candidates, and any attempt to project final results from preliminary figures requires considerable guesswork.

Republicans working in critical states are nevertheless openly worried. Tanya Karabanovs, a volunteer with the Ohio Republican Party, described the party’s difficulty motivating voters in blunt terms.

“This is really a weird cycle,” Karabanovs told The New York Times. “There’s no way to feel confident about any of the races, honestly.”

Michigan Republicans have faced their own turmoil over turnout concerns. Jackson Karki resigned as chair of the Marquette County Republican Party in September after publicly warning that the party was struggling to mobilize voters while Trump’s popularity with the GOP base was sinking.

“The vibes on the ground are the worst I’ve seen in my life,” Karki wrote on X in mid September. “No one wants to promote candidates, no one wants to knock doors, no one wants to do shit. Attendance for any right wing event is at all time lows anywhere I go. Thank you Donald Trump for ruining it for us… and handing the country over to socialism.”

The turnout troubles also reflect months of polling showing Republican voters becoming disillusioned with President Donald Trump. The source of that anger includes his war in Iran and tariffs that have driven up gas prices and produced economic hardship across the country.

Some of those voters are threatening either to skip the election or support Democrats. If that dissatisfaction translates into ballots, Republicans could find themselves staring at a blue tsunami rather than the majorities they are trying to defend.

A Washington Post, ABC News, and Ipsos poll released Sunday found that 33% of Americans approved of Trump’s performance as president. That was the lowest approval rating the poll had recorded during either of his terms.

The same poll found Democrats leading Republicans by 13 points on the generic congressional ballot among people who said they were certain to vote or had already voted. The early ballot numbers now suggest that the polling may not merely be accurate, but could even be underestimating Democratic strength.

The outcome will be known in 15 days. Until then, the GOP has to confront an uncomfortable reality: Its voters are not showing up at the pace Republicans need, while Democrats are banking ballots across the states that could determine control of Congress.