The Right to Rise super PAC supporting former Florida Gov. Jeb Bush's presidential bid released a new commercial in Iowa criticizing rival Marco Rubio for his lackluster Senate attendance record. The ad campaign, running for two weeks at a cost of $1.4 million, portrays Rubio as being more concerned with raising money for his presidential campaign than upholding his duties as a senator, reported the Des Moines Register.

"Over the last three years, Rubio has missed important national security hearings and missed more total votes than any other senator," says the narrator.

The 30-second ad mentions two recent times Rubio missed critical meetings because he was raising money: one top-secret briefing after the Paris terrorist attacks, which left 130 people dead, and another non-specified event after the shooting in San Bernardino, Calif., which left 14 dead.

"Days after the Paris attacks, senators came together for a top-secret briefing on the terrorist threat," says the narrator. "Marco Rubio was missing, fund-raising in California instead." The ad then displays a picture of an empty seat.

"Politics first: that's the Rubio way," concludes the ad.

Rubio's presidential campaign shot back today. "Bush's team dishonestly omits that Marco is on the Senate's Intelligence Committee, where he attended the highest level briefings on the Paris attacks," said Rubio spokesman Alex Conant in a statement, according to Politico. "No other candidate for president has received more classified Intelligence briefings or better understands the threats facing our nation today than Marco. It's sad to see Jeb's 'joyful' campaign reduced to such intellectual dishonesty."

Rubio's team said he missed the briefing because he had already attended the Intelligence Committee meeting, which is "typically more in-depth and contains higher classified information than other briefings."

While Bush himself isn't behind the ad, in October he also slammed Rubio for his Senate record during the third Republican debate, saying, "I'm a constituent of this senator, and I helped him, and I would expect that he would do constituent service, which means that he shows up to work. But Marco: When you signed up for this, this is a six-year term, and you should be showing up to work."

Rubio said during the debate that he is missing votes because he is "frustrated" with the Senate. "That's why I'm missing votes. Because I am leaving the Senate. I am not running for re-election," reported the Washington Post.

After he failed to show up for a vote on the omnibus budget and tax bill earlier this month, rival candidate Sen. Rand Paul called on him to resign, while members of Sen. Ted Cruz's campaign tweeted the hashtag #NoShowMarco.