(NewsNation Now) — Campaigns and outside groups are making a final push to turn out Georgians whose votes will determine control of the U.S. Senate, from text messages and television ads to dueling visits from President-elect Joe Biden and outgoing President Donald Trump.

More than 2.5 million people — about half the turnout of last month’s presidential election — had already cast their ballots early, in person or by absentee ballot, by Wednesday morning.

With margins in the Jan. 5 runoffs expected to be tight, the campaigns for Republican U.S. Sens. David Perdue and Kelly Loeffler and Democratic challengers Jon Ossoff and Raphael Warnock are all focused on mobilizing voters.

That means everything from individual voter contacts urging early voting, which ends Thursday, to last-minute campaign stops from national headliners trying to boost Election Day turnout. The Democrats’ campaigns announced Wednesday that Biden would campaign Monday in Atlanta with Ossoff and Warnock. Trump already had announced plans to rally Monday evening, just hours before polls open, with the Republican senators in the north Georgia town of Dalton. Vice President-elect Kamala Harris, meanwhile, will come to Savannah on Sunday.

In the nearly two months since the general election in November, Georgians have been inundated by radio and television advertisements, mailings, calls, text messages and even hand-written notes from out-of-state residents urging them to vote.

Runoff elections historically draw a much lower turnout than general elections, and in Georgia, they have favored Republican candidates in the last decade. But in this unique election — with national attention, money pouring in and control of the Senate at stake — the normal rules don’t seem to apply.

Rather than dropping dramatically, early voting for the runoff is only about 20% lower than the early turnout at the same point before the general election, though missed days over Christmas make a direct comparison difficult.

In-person early voting ends statewide Thursday, though some counties observe New Year’s Eve as a holiday so Wednesday will be their last day. Absentee ballots can be returned by mail or in drop boxes to be counted as long as they’re received by 7 p.m. on Election Day.

Perdue and Loeffler both failed to win a majority of votes in the general election last month, forcing the runoffs.

The president already held a rally earlier this month in Valdosta, in south Georgia. Vice President Mike Pence and other high-profile Republicans have also traveled to Georgia.