In the campaign’s final stretch, both parties are scrambling to mobilize voters as Republicans try to hold the Senate and Democrats look for breakthroughs in states long considered safely Republican.

More than 40 million Americans had voted or mailed in ballots by Wednesday night, according to the University of Florida’s Election Lab; in Georgia, early voting had also topped 2 million ballots by Wednesday morning.

Republicans have redirected significant last-minute resources to four vulnerable Senate races in Kansas, South Carolina, Nebraska and Mississippi. The Republican-aligned Senate Leadership Fund spent $14 million across those states in the campaign’s penultimate week, including more than $5 million in Kansas and about $5 million in South Carolina.

Kansas has become a particular worry: an early-October Trafalgar Group poll put Democrat Adam Hamilton one point ahead of incumbent Roger Marshall, whose campaign has faced criticism over legal action against patients with unpaid bills, time spent in Florida and a perceived lack of urgency.

South Carolina is another unexpected battleground. A recent New York Times/Siena poll showed a tie, despite President Trump campaigning there to boost Republican turnout and Republican interim Senator Darline Graham having his endorsement.

Democrats see the South Carolina contest as a chance to end their nearly three-decade absence from the state’s Senate representation, while Republicans are spending to help Graham, who has struggled to mobilize Trump’s base.

Republican operatives say they are encouraged that Democrats have not recently expanded their leads in several key races, but Democratic aides are increasingly concerned about Michigan, where Abdul El-Sayed’s campaign has faced divisions over Israel and outreach to Black voters.

Michigan Representative Haley Stevens, who lost the Democratic Senate primary to El-Sayed, has criticized his campaign and urged him to disavow an outside group’s ad she called fear-mongering about Israel and to remove an ad featuring Tucker Carlson. Stevens says she will vote for El-Sayed but will not campaign with him.

Barack Obama held a large rally in suburban Atlanta to support Georgia Democrats, including Senator Jon Ossoff and gubernatorial candidate Keisha Lance Bottoms, as early turnout climbed above 2022 levels.

Ossoff held an eight- to 10-point polling lead over Republican Mike Collins, while Bottoms was statistically tied with Republican Rick Jackson; a Bottoms win would end Georgia’s Republican trifecta, in place since 2004.

Republicans spent an estimated $183 million on television ads attacking Democrats over transgender issues through Oct. 25, funding about 217,000 spots in an effort to shift attention away from economic concerns.

The final campaign schedule brought Trump to Ohio, North Carolina and Georgia, while Barack Obama campaigned in Atlanta; Pete Buttigieg and Bill Clinton were also scheduled to campaign in Mississippi for Democrat Scott Colom against Republican Sen. Cindy Hyde-Smith.