A day after the Electoral College confirmed his presidential victory, Joe Biden will travel to Georgia on Tuesday to campaign for two Democratic U.S. Senate candidates whose Jan. 5 runoff elections could make or break his domestic policy agenda.

Biden’s narrow win in the Southern state in November’s presidential election completed its transformation from Republican stronghold to one of the country’s most competitive political battlegrounds.

Republican Senators David Perdue and Kelly Loeffler are facing Democrats Jon Ossoff and Raphael Warnock, respectively, in twin races that will determine which party controls the U.S. Senate when Biden takes office on Jan. 20.

If the Republicans win either contest, they would maintain power in the Senate, allowing them to thwart many of Biden’s ambitious legislative goals on issues such as the coronavirus, the economy and climate change. A Democratic sweep would give the party control of the White House and Congress, where it also has a majority in the U.S. House of Representatives.

Biden’s trip to Atlanta comes nine days after President Donald Trump traveled to Georgia in support of Perdue and Loeffler. The president-elect’s visit also coincides with early in-person voting, which began on Monday as hundreds of Georgians braved rainy weather to stand in line.

As in November, many voters are expected to cast ballots by mail amid the ongoing coronavirus pandemic. Thus far, more than 1.2 million residents have requested absentee ballots, and more than 260,000 have already sent them in, according to the U.S. Elections Project at the University of Florida.

Biden’s win has boosted Democratic hopes of capturing both seats, along with aggressive efforts to register voters and changing demographics that have pushed the electorate away from Republicans.

Perdue ran ahead of Trump in the Nov. 3 election, however, finishing ahead of Ossoff but just shy of the 50% required to avoid a runoff under state law. A third-party candidate received about 2% of the vote.

The other race had a large field of candidates in November due to its status as a special election because Loeffler was appointed to her seat to fill a vacancy. Warnock and Loeffler finished in the top two positions, each well short of 50%.

Turnout issues

Hundreds of millions of dollars have poured into the state from both political parties as well as an array of outside political groups.

Both sides face turnout challenges in the midst of the pandemic and without the polarizing Trump at the top of the ballot to turn out votes from his deeply loyal supporters and also from detractors with deep animosity toward him.

Some Republicans in the state have expressed concern that Trump’s repeated insistence, without evidence, that the November results were fraudulent may drive down turnout among his most ardent supporters.

Biden secured the presidency on Monday after the Electoral College formalized his win. Under U.S. law, the president is not elected by a majority of the popular vote but by the Electoral College, which awards electoral votes to the winner of each state based on congressional representation.