Jeb Bush and Marco RubioMarco Antonio RubioGOP lawmakers raise concerns over research grants to colleges with Confucius Institutes Paid family leave could give new parents a much-needed lifeline GOP looks to injure Nelson over Russia comments MORE’s long-simmering feud in the GOP presidential race burst into the open on Wednesday night over Rubio’s missed votes in the Senate.

Rubio was challenged by a CNBC debate moderator for missing more votes than any other senator this year and being a "young man in a hurry" in his political career, moving on to a new office before finishing out a full term. The Florida lawmaker responded forcefully with a line that won him wild applause from the crowd.

“That’s exactly what the Republican establishment says too,” Rubio said. “'Why don’t you wait in line?' Wait for what? This country is running out of time, we can’t afford to have another eight years like the last four. ... The time to act is now. The time to turn the page is now.”

But before the moderators could move on, Bush interjected, pointing out that as a fellow Florida resident, Rubio represents him in the Senate.

“I’m a constituent of the senator and I helped him and expected he would show up to work,” the former governor said. “But Marco, when you signed up for this, this was a six-year term. I mean, literally the Senate, what is it a French work week where you have three days to show up? You can campaign, or just resign and let someone else take the job.

"There are a lot of people in Florida living paycheck to paycheck looking for a senator that will fight for them each and every day.”

Rubio responded: "The only reason [Bush is launching this attack] is because we're running for the same position and someone has convinced you that attacking me is going to help you." The crowd cheered.

Rubio had a ready-made comeback, firing back at Bush by saying that he never criticized Arizona Sen. John McCainJohn Sidney McCain15 senators miss votes despite McConnell's criticism of absentees What crime did Manafort allegedly commit? Primary challenge to Trump? It could help him in 2020 MORE in his 2008 run for the White House for missing votes.

“I don’t remember you ever complaining about his voting record, the only reason you’re doing it is because we’re running for the same position and you’re convinced that attacking me is going to help you,” the senator said.

Late Tuesday, Rubio’s hometown paper the Sun Sentinel released a blistering editorial imploring he resign.
“Your job is to represent Floridians in the Senate,” the paper wrote. “Either do your job, Sen. Rubio, or resign it.”
At the debate, Rubio blasted the paper, which endorsed his Senate candidacy in 2010, pointing out that the editors did not similarly call out then-Sens. Barack ObamaBarack Hussein ObamaC-SPAN forced into 7-second delay after caller's racist tirade against Obama Judge dismisses Bevin lawsuit against Kentucky Medicaid activists Primary challenge to Trump? It could help him in 2020 MORE and John KerryJohn Forbes KerryVoters will punish Congress for ignoring duty on war and peace Trump draws bipartisan fire over Brennan Hillicon Valley: Trump revokes Brennan's security clearance | Twitter cracks down on InfoWars | AT&T hit with crypto lawsuit | DHS hosts election security exercise MORE for missing votes while they ran for office.
“It’s evidence of the bias that exists in the American media today,” Rubio said.