Conservative groups are ganging up on the airwaves against Sen. Thad CochranWilliam (Thad) Thad CochranGOP senators ask Trump to hold off on Venezuelan oil sanctions Both sides of the aisle agree — telemedicine is the future Overnight Finance: GOP offers measure to repeal arbitration rule | Feds fine Exxon M for Russian sanctions violations | Senate panel sticks with 2017 funding levels for budget | Trump tax nominee advances | Trump unveils first reg agenda MORE (R-Miss.), but he's still fighting back for his political life ahead of his June primary. 

The Club for Growth is hitting Sen. Thad Cochran (R-Miss.) with a six-figure ad buy that attempts to align him with President Obama, Jimmy Carter and George H.W. Bush. 

“Five Decades in Washington is enough," a narrator in the ad says. 

The conservative group has endorsed Cochran's primary opponent, Chris McDaniel in the GOP primary. The group released a number of ads in February targeting Cochran on tax increases and the debt. 

The ad cites Cochran's votes to "massively expand federal control of education" during the Carter administration.

“Cochran votes for George H.W. Bush's 'Read my lips' tax increase," the narrator says, referencing the former president's broken promise about not raising taxes during his term. 

Senate Conservatives Action also released a television ad touting McDaniel, showing him arguing in a speech to eliminate the national debt and the healthcare law. 

"We will not compromise on the United States constitution," McDaniel says in the SCA ad

Cochran released his own ad Monday blasting McDaniel for initial comments he made suggesting he wouldn't have voted for Mississippi disaster relief after Hurricane Katrina. 

"If Chris McDaniel won't do anything for Mississippi, why should Mississippians do anything for Chris McDaniel," the narrator says in the ad.