Ted Cruz had barely been in the Senate for two months in March when Arizona Republican Sen. John McCain famously voiced his frustration with the new Texas lawmaker by calling him a “wacko bird.”

The two seem to have never quite gotten along, even though McCain apologized soon after he made the comment. But Cruz, who this week is finding himself at the receiving end of Republican vitriol for his plan to risk a government shutdown in order to defund the 2010 federal health care law, doesn’t think much of McCain either.

In a new lengthy GQ profile, Cruz told the magazine that conservatives were “embarrassed” to vote in 2008 — the year that McCain was the Republican presidential nominee.

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

The profile of Cruz, a politician who has ignited speculation about whether he himself may run for president in 2016 by speaking to Republican groups in early-voting states such as New Hampshire and Iowa, provides a glimpse into Cruz’s background as a fiercely ambitious — some might say cocky — Ivy League-educated immigrants’ son who is shaking up the GOP.

According to the article, despite Cruz’s rapid rise, he still has work to do to win the approval of McCain.

As one McCain aide told GQ: “He (expletive) hates Cruz.”