ATLANTA (AP) — Democratic Senate challenger Jon Ossoff debated an empty podium Sunday, hammering Georgia Sen. David Perdue as a “coward” for skipping the pair’s lone scheduled debate ahead of twin Jan. 5 runoffs that will determine which party controls the Senate at the start of Democrat Joe Biden’s presidency.

Ossoff suggested Perdue, the first-term Republican whose prolific stock trading has drawn attention during the COVID-19 pandemic, left his podium vacant because he didn’t want to “incriminate himself” over his personal financial activities that the challenger summed up as “cartoonish abuse of power.”

“It shows an astonishing arrogance and sense of entitlement for Georgia’s senior U.S. senator to believe he shouldn’t have to debate at a moment like this in our history,” Ossoff said, criticizing Perdue for avoiding the debate as the coronavirus pandemic rages and Congress continues to be at loggerheads over a new round of economic relief.

Ossoff’s one-man show is the undercard for the evening. Republican Sen. Kelly Loeffler and Democratic challenger Raphael Warnock are set to share the stage later Sunday evening. Republicans need to retain one of the seats to keep their Senate majority and stymie the Biden administration. Democrats must sweep to position Vice President-elect Kamala Harris as the Senate’s tiebreaking vote.

The runoffs have put Georgia squarely in the national political spotlight, drawing tens of millions of dollars and a flood of field workers and volunteers from around the country.

President Donald Trump came to the state Saturday to campaign with both Republican senators in Valdosta. Vice President Mike Pence appeared the day before in Savannah, as former President Barack Obama headlined a virtual rally for Democrats. Biden, the first Democratic presidential candidate to win Georgia since 1992, has promised to visit before the runoff, acknowledging that the outcome will shape the legislative reach of his presidency.

Republicans have embraced the national consequences, framing Ossoff and Warnock as harbingers of a socialist takeover of Washington. Neither are socialists but the GOP wants to stoke its base for a second round of voting with the fear of Democrats controlling both ends of Pennsylvania Avenue. Democrats already have protected their House majority, and the Republican argument concedes Trump’s loss to Biden, even if the president himself has refused to acknowledge his defeat.

Beyond the national stakes, Ossoff has zeroed in on Perdue’s financial activities. The Associated Press and other media have reported details of key trades Perdue made after members of Congress began receiving classified briefings about COVID-19 but while Perdue and other officials were downplaying its dangers in public. Perdue’s trades also involved companies whose business activities fall under jurisdiction of some of the senator’s committees.

Ossoff brushed aside a moderator’s reminder that Senate ethics officials and the Department of Justice have not found any legal wrongdoing on Perdue’s part.

“His blatant abuse of his power and privilege to enrich himself is disgraceful,” Ossoff said. “He can’t defend the indefensible. ... The standard for our elected officials must be higher than merely evading prosecution.”

Both runoffs are required under Georgia state law because no candidate reached 50% in November. Perdue fell just short of defeating Ossoff because a Libertarian candidate won a small slice of the vote, while Warnock led Loeffler in a 20-way field in which no candidate came close to 50%.

Loeffler and Perdue rallied Saturday in Valdosta with Trump, who came to the state to support the candidates despite continuing questions over whether Trump's unproven attacks on Georgia's presidential balloting will cause some of his Republican supporters to shy away from voting in the runoffs.

Georgia Secretary of State Brad Raffensperger continued to defend the integrity of the presidential election Sunday. As a Republican, Raffensperger said on ABC's “This Week” that he wants Loeffler and Perdue to do well even though they both called for him to be removed from office, echoing Trump.

“These distractions, this disunity, it does make it more difficult,” Raffensperger said.