Matthias Schrader / AP Sen. John McCain

Updated 12:52 pm ET. Always one to speak -- or Tweet -- his mind, Sen. John McCain (R-AZ) Monday made a joke comparing Iranian leader Mahmoud Ahmadinejad to a monkey, something one Republican congressman charged was “racist.”

“So Ahmadinejad wants to be first Iranian in space - wasn't he just there last week?” McCain said in a tweet that also linked to a story about Iran launching a monkey into space.

Some didn’t take so kindly to the not-so-diplomatic quip, prompting McCain, 76, to respond: “Re: Iran space tweet - lighten up folks, can't everyone take a joke?”

Seeing that, Michigan congressman Rep. Justin Amash, 32, shot back.

“Maybe you should wisen up & not make racist jokes,” Amash tweeted.

Not everyone on the right agreed with Amash. Conservative John Podhoretz, for example, Tweeted this: "How dare McCain say something demeaning & disparaging abt the foremost anti-Semite on the planet." And this: "So...it's defend-the-Jew-hater-from-the-war-hero day."

It’s not the first time McCain’s made a joke about Iran that landed him in some hot water. During his run for president in 2007, McCain sang about bombing the country.

Asked by a GOP primary voter when the U.S. would send an “air-mail message to Tehran,” McCain said, “That old Beach Boys’ song, ‘Bomb Iran?’ Bomb, bomb, bomb—, anyway.”

McCain’s response then as now? It’s just a joke -- "get a life.”

“When veterans are together, veterans joke,” McCain said at the time. “And I was with veterans and we were joking. And if somebody can’t understand that, my answer is, ‘Please, get a life.’”