A lengthy profile on Sen. Ted Cruz (R-TX) in the October issue of GQ may compound his already-contentious relationship with Sen. John McCain (R-AZ).

In the piece by Jason Zengerle, an unnamed adviser to McCain explained the Arizona senator’s aversion to Cruz.

“He fucking hates Cruz,” the adviser told Zengerle. “He’s just offended by his style.”

But Cruz made it clear that he’s no fan of McCain either with a thinly veiled shot at the 2008 GOP presidential nominee.

“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 went after both Cruz and Sen. Rand Paul (R-KY) earlier this year over their criticism of U.S. drone policy, calling the two junior senators “wacko birds.” More recently, McCain has criticized Cruz for leading the quixotic effort to defund Obamacare and risk a government shutdown.

The Arizona senator said last week it is “not rational” to believe that the Senate will repeal the new health care law.

This post has been updated.