Sen. Ted CruzTed CruzA guide to the committees: Senate Trump wants to cut red tape? He should start with the CFPB. Why President Trump should choose Maureen Ohlhausen to lead the FTC MORE (R-Texas) took a veiled swipe at Sen. John McCainJohn McCainA guide to the committees: Senate Webb: The future of conservatism New national security adviser pick marks big change on Russia MORE (R-Ariz.) in a GQ profile released Monday, saying he was “embarrassed” to have voted Republican in 2008.

“I don’t know a conservative who didn’t feel embarrassed voting in 2006 or 2008,” Cruz said. “I think the Republican Party lost its way. We didn’t stand for the principles we’re supposed to believe in.”

McCain was the Republican presidential candidate in 2008. Former Alaska Gov. Sarah Palin, who endorsed Cruz in his 2012 Senate campaign, was McCain's running mate. 

McCain and Cruz have been locking horns since the combative Texas Republican first arrived in the Senate. The two have been openly critical of one another on a range of issues, including drone strikes, foreign policy and the nomination of Defense Secretary Chuck HagelChuck HagelWho will temper Trump after he takes office? Hagel: I’m ‘encouraged’ by Trump’s Russia outreach Want to 'drain the swamp'? Implement regular order MORE.

McCain, at one point, referred to Cruz and fellow Tea Party favorite Sen. Rand PaulRand PaulCongress must reform civil asset forfeiture laws ­ObamaCare fix hinges on Medicaid clash in Senate A guide to the committees: Senate MORE (R-Ky.) as “wacko birds.”

“He [expletive] hates Cruz,” a McCain aide says in the GQ profile.

McCain and Cruz are presently at odds over Cruz’s attempt to defund the president’s healthcare law. Cruz and some Tea Party lawmakers are threatening a government shutdown, saying that any resolution to continue funding the government must not include money to implement ObamaCare.