A super-PAC backing Marco RubioMarco RubioWhat the 2016 election can tell us about 2018 midterms Fight over water bill heats up in Senate Brown-Mandel Ohio Senate race will be brutal referendum on Trumpism MORE is hitting back at Jeb Bush, calling him "desperate" for his attacks on the Florida lawmaker's Senate attendance.

“Desperate candidates say desperate things, and Jeb Bush is desperate,” the narrator says in the new TV ad titled "Security," which launched Thursday from Conservative Solutions PAC. The ad will air statewide in Iowa.

ADVERTISEMENT
It comes after an ad from Right to Rise, a super-PAC supporting Bush, on Tuesday, knocked Rubio for missing a top-secret briefing days after the Paris terrorist attack to fundraise.

Rubio campaign’s has called the charge unfounded, noting that he attended a select committee hearing regarding the attack days before the briefing.

Bush and other GOP rivals including New Jersey Gov. Chris Christie have chided the Florida senator for missing votes and Senate hearings.

The pro-Rubio spot also invokes Sen. Chuck GrassleyChuck GrassleyBusiness groups express support for Branstad nomination 10 no-brainer ways to cut healthcare costs without hurting quality Senate GOP: National museum should include Clarence Thomas MORE (R-Iowa), displaying a clip from a local TV station with a headline saying that the state’s popular senator is defending Rubio.

“His attacks on Marco Rubio have been dismissed and debunked by our own Sen. Grassley,” the ad says. “The fact- Rubio has attended more classified national security briefings this year than any other candidate.”

The ad closes by describing Rubio as "the conservative most feared by Hillary ClintonHillary Rodham ClintonKeith Ellison is the leader the DNC needs Overnight Cybersecurity: Retired general picked to head DHS | Graham vows to probe Russian election interference McCarthy’s ghost smiles as Dems point the finger at Russia MORE and Jeb Bush."

Rubio sits in third place in both national and Iowa polls behind GOP rivals Donald TrumpDonald TrumpKeith Ellison is the leader the DNC needs Overnight Cybersecurity: Retired general picked to head DHS | Graham vows to probe Russian election interference Gingrich: Japanese 'displayed professional brilliance' in Pearl Harbor attack MORE and Sen. Ted CruzTed CruzArk., Texas senators put cheese dip vs. queso to the test Pentagon's suppressed waste report only tip of the inefficient machine Markos Moulitsas: Kill the filibuster MORE (R-Texas). But Bush lags even farther behind in the single digits.

The Iowa caucuses will be held on Feb. 1.