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(NewsNation) — Former President Donald Trump wasn’t at the fourth Republican presidential debate Wednesday, but that didn’t stop the GOP candidates from calling attention to his age, broken promises and even his character.

Florida Gov. Ron DeSantis urged Republican voters to support the next generation and said “Father time is undefeated,” casting doubt on Trump’s mental fitness.

Former New Jersey Gov. Chris Christie was more pointed in his criticism of the former president. He called Trump “an angry, bitter man” who’s looking to “exact retribution” after the former said he would be a dictator on the first day of his administration if reelected.

DeSantis questions Trump’s age

When asked whether he thinks Trump is mentally fit to be president, DeSantis called out the former president’s age. If elected, Trump, 77, would be the second oldest president after current President Joe Biden.

“The idea that we’re going to put someone up there that’s almost 80 and there’s going to be no effects from that? We all know that that’s not true,” he said.

The Florida governor — who previously had a friendly relationship with Trump — emphasized the importance of having someone younger in the White House before attacking Trump’s record in office.

“He didn’t clean up the swamp. He said he was going to drain it, he did not drain it,” DeSantis said. “He said he was going to build the wall and make Mexico pay for it; we don’t have the wall.”

After being pressed by NewsNation’s Elizabeth Vargas, DeSantis would not say if he thought Trump was mentally fit enough for another term.

“We should not nominate somebody who’s almost 80 years old.”

Haley blasts Trump on China

Former U.S. ambassador to the United Nations under Trump, Haley criticized her former boss on China, saying that though he was good on trade, “that’s all he was.”

“He allowed fentanyl to continue to come over,” she said. “He would give them technology that would build up their military and hurt us. He allowed the Chinese infiltration for them to buy up farmland, to put money in our universities and to continue to do things that were harmful for America.”

Haley also weighed in on immigration.

In response to a clip of Trump saying that “if you empathize with radical Islamic terrorists and extremists, you’re disqualified” from coming to America, Haley rejected the idea of an outright religious litmus test but agreed with the former president’s premise.

“I don’t think that you have a straight-up Muslim ban as much as you look at the countries that have terrorist activities that want to hurt Americans. You can ban those people from those countries,” she said.

Ramaswamy accuses opponents of ‘bootlicking’

The biotech entrepreneur accused his opponents of “licking Donald Trump’s boots” to get “money and endorsements” before commending the former president for going after “the deep state.”

“I think the real enemy is not Donald Trump, it’s not even Joe Biden, it is the deep state that at least Donald Trump attempted to take on,” he said.

During the debate, Ramaswamy rebuked his GOP competitors for “Monday morning quarterbacking” the decisions Trump made.

On the campaign trail, Ramaswamy has called Trump the best president of the 21st century and consistently defended him.

Christie calls Trump ‘dictator’ and ‘bully’

Christie didn’t mince words when criticizing Trump, calling him a “dictator” and a “bully” at Wednesday’s debate.

“This is an angry, bitter man who now wants to be back as president because he wants to exact retribution on anyone who has disagreed with him, anyone who has tried to hold him to account for his own conduct,” the former New Jersey governor said.

Christie blasted his GOP opponents over their reluctance to denounce Trump. He defended his decision to stay in the race despite his anemic polling and said he’s there to be honest about the former president.

“I’m in this race because the truth needs to be spoken, [Trump] is unfit,” Christie said. “I’ve got these three guys who are all seeming to compete with Voldemort, he who shall not be named. They don’t want to talk about it.”