Sen. Marco RubioMarco Antonio RubioOvernight Defense: Tillerson, Trump deny report of rift | Tillerson says he never considered resigning | Trump expresses 'total confidence' in secretary | Rubio asks Army to kick out West Point grad Rubio asks Army to kick out West Point grad with pro-communist posts GOP establishment doubts Bannon’s primary powers MORE (R-Fla.) on Tuesday backed freshman Rep. Tom CottonTom CottonHouse bill set to reignite debate on warrantless surveillance Republicans jockey for position on immigration The Hill's 12:30 Report MORE (R-Ark.) for the Senate in his first endorsement of the 2014 cycle.

The endorsement comes with a twist, as Cotton is a strident opponent of the bipartisan immigration bill that Rubio helped pass through the Senate.

Rubio said Cotton would stick to his guns if elected to the Senate from Arkansas.

ADVERTISEMENT
"Once elected, we can be confident that Tom will be another conservative friend in Washington who will ensure that our children and grandchildren inherit an exceptional America from this generation," Rubio said in an email from his leadership PAC.

"He won't stand down when it comes to repealing ObamaCare, fighting to lower our runaway debt, and turning back the tide of big government that has taken over Washington in recent years."

Rubio and Cotton have similar political profiles.

Both are staunch fiscal conservatives bouyed by the Tea Party movement, and have been embraced by Washington's GOP establishment.

The two men also have hawkish views on foreign policy that are at odds with the libertarian streak that has taken hold in the GOP.

Cotton is running against Sen. Mark PryorMark PryorMedicaid rollback looms for GOP senators in 2020 Cotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm MORE (D-Ark.) in a must-win race for Senate Republicans if they hope to regain control of the upper chamber.