ATLANTA — In a televised debate on Sunday night, Senator Kelly Loeffler, a Georgia Republican, declined to say that President Trump had lost the election, arguing instead that the president had “every legal recourse available” to pursue his baseless assertion that the vote in Georgia was rigged against him.
Ms. Loeffler, whose runoff race is one of two in Georgia that will determine control of the Senate on Jan. 5, has emerged as a staunch defender of Mr. Trump. She used the debate to label her Democratic opponent, the Rev. Raphael Warnock, as a “radical liberal” more than a dozen times over the course of an hour.
Mr. Warnock criticized Ms. Loeffler, one of the richest members of the Senate, for making a large number of stock trades after she attended a briefing on the coronavirus in January. Ms. Loeffler did not answer directly when asked whether members of Congress should be barred from trading stocks.
“Look, what’s at stake here in this election is the American dream,” Ms. Loeffler said, calling the question of her stock trades “a left-wing media lie.” She added, “This is an attack on every single Georgian who gets up every day to work hard to provide a better life for their family.”
Ms. Loeffler’s trades and those of two other senators were investigated by the Justice Department, but the department announced in May that it would not pursue insider trading charges against them. A Senate Ethics Committee investigation also found no evidence of violations.
The debate came one day after Mr. Trump held a rally in Georgia in which he falsely claimed that he had won the state — and after he made a phone call to Gov. Brian Kemp, asking him to call a special session of the Republican-controlled legislature so that lawmakers could appoint new electors who would subvert the will of the state’s voters when the Electoral College meets on Dec. 14.
In a statement on Sunday, Mr. Kemp and Lt. Gov. Geoff Duncan, both Republicans, said that a special session would not be called in Georgia, reiterating a position they had taken previously. “Doing this in order to select a separate slate of presidential electors is not an option that is allowed under state or federal law,” they said.
Mr. Kemp and Mr. Duncan added that state law allows the legislature only to “direct an alternative method for choosing presidential electors if the election was not able to be held on the date set by federal law.”
Ms. Loeffler and Georgia’s other Republican senator, David Perdue, have both stuck by the president, attending the rally with him in Valdosta, Ga., on Saturday. But prominent Republicans are worried that Mr. Trump’s airing of his grievances about his loss in the state might convince his supporters that Georgia’s voting system is indeed rigged and that they should sit out the crucially important runoff elections.
Losses by both Ms. Loeffler and Mr. Perdue would hand control of the Senate to the Democrats.
At the debate, Ms. Loeffler hammered repeatedly on her theme that Mr. Warnock — the pastor at Ebenezer Baptist Church in Atlanta, where the Rev. Dr. Martin Luther King Jr. once preached — was dangerously out of step with Georgia values. She said that he had criticized the police from the pulpit and advocated “socialism” and abortion rights.
Mr. Warnock also portrayed Ms. Loeffler as being out of touch, bringing up her stock trades and criticizing her initial opposition to Congress’s relief package for people and businesses affected by the coronavirus pandemic. (Ms. Loeffler eventually voted for the $2 trillion package in March.)
The debate came at the end of a day made particularly tense by Mr. Trump’s assertion, at his Saturday night rally, that the presidential election had been “rigged” in Georgia, a state that two recounts have shown he lost. The latest tally has him losing by about 12,000 votes.
Georgia has already seen remarkable Republican infighting over Mr. Trump’s push to reverse the results of the race. Violent threats against elections workers have grown so problematic that a top state elections official, Gabriel Sterling, a Republican, last week asked the president to check his inflammatory language.
On Sunday morning, high-ranking Georgia officials from Mr. Trump’s own party pushed back, yet again, against the president’s bogus assertions of widespread electoral fraud.
Secretary of State Brad Raffensperger, a Republican who has become one of the chief targets of Mr. Trump’s wrath in recent days, went on the ABC program “This Week” and addressed the president’s phone call to Mr. Kemp.
Mr. Raffensperger, who, like Mr. Kemp, supported Mr. Trump in the election, said that holding a special session would amount to “nullifying the will of the people.”
“At the end of the day, the voice of the people were spoken,” he said. “I’m disappointed as a conservative Republican also.”
The other runoff race in Georgia pits Mr. Perdue, a former corporate executive, against Jon Ossoff, a 33-year-old Democrat and documentary filmmaker. Mr. Perdue declined to attend a debate with Mr. Ossoff on Sunday, which resulted in a strange 30-minute session in which Mr. Ossoff faced off against an empty lectern.
Mr. Ossoff called Mr. Perdue a “coward” for not debating and criticized what he described as the senator’s early understatement of the threat posed by the coronavirus. “The reason that we are losing thousands of people per day to this virus is because of the arrogance of politicians like David Perdue,” Mr. Ossoff said. “So arrogant that he disregarded public health expertise, and so arrogant that he’s not with us here today to answer questions.”
He added, “He believes the Senate seat belongs to him.”
At one point in Ms. Loeffler’s debate with Mr. Warnock, she asked him about his arrest in 2002 for obstructing law enforcement officials who were conducting a child abuse investigation at a summer camp in Maryland that was affiliated with Mr. Warnock’s church at the time.
Mr. Warnock responded that he was “working at trying to make sure that young people, who were being questioned by law enforcement, had the benefit of counsel, a lawyer or a parent.” He added, “The law enforcement officers actually later thanked me for my cooperation and for helping them.”
The website PolitiFact and others have noted that the charges were dismissed by a judge after a prosecutor said there had been a “miscommunication” with Mr. Warnock, who had been “very helpful” with the investigation.
Richard Fausset reported from Atlanta, and Rick Rojas from Nashville.