WASHINGTON — John McCain is making it very clear that he isn’t just going to go along with everything President Trump proposes, despite the fact they are both Republicans.

The Arizona senator just won a six-year term so he isn’t concerned about being re-elected. And just a few days into the new administration, he’s showing that he has no problem speaking out against the president.

“Look, there's no evidence of that and I think that those who allege that have to come up with some substantiation of the claim,” McCain said Wednesday on MSNBC’s Morning Joe about Trump’s claim that millions have people voted illegally and cost him the popular vote in the election.

Trump announced there would be “a major investigation into VOTER FRAUD” on Wednesday. The investigation will be to look into his unsubstantiated claim that he lost the popular vote because of millions of illegal votes.

“Listen, I won by 14 points. I'm absolutely sure that there was not a single illegal vote in that election in Arizona,” McCain said about his re-election to the Senate in November.

McCain also broke withTrump on reports that the president is considering revisiting U.S. policy against waterboarding and other aggressive interrogation techniques.

“The President can sign whatever executive orders he likes. But the law is the law. We are not bringing back torture in the United States of America,” the former POW and military advocate said in a statement issued Wednesday morning.

“Even though the army field manual can be reviewed it still does not allow to return to the use of torture, including waterboarding,” McCain said on MSNBC. “I’m very confident it wouldn’t stand a day in court if they tried to restore that.”

McCain was responding to reports of a draft of an executive order that would reopen secret prisons and allow for harsh interrogation for “high-value alien terrorists” that Trump is reportedly considering.

White House spokesman Sean Spicer has denied that the draft came from the White House.

Trump campaigned on expanding torture laws, including waterboarding, which McCain is against.

McCain also isn’t giving Trump’s Cabinet picks the same deference most of his Republican colleagues are. He attacked Trump’s pick for the Office of Management and Budget over his history of votes on military spending and support of government shutdowns in budget negotiations.

“I’m interested in what our military needs and whether they’re receiving it. It’s clear from your record that you’ve been an impediment to that for years,” McCain said to South Carolina Rep. Mick Mulvaney during a hearing on Tuesday.

McCain told MSNBC he was “leaning against” voting for Mulvaney Wednesday.

And even though he eventually voted to confirm Trump’s pick for secretary of state, McCain made retired Exxon Mobil CEO Rex Tillerson’s confirmation process bruising by repeatedly bringing up questions about Tillerson’s ties to Russia.

Trump is not the first Republican president that McCain has spoken out against. He’s developed the reputation as being a “maverick” which he touted when he ran for president in 2008.

But for much of the campaign McCain kept quiet about Trump even after Trump said McCain wasn’t a war hero because he had been captured during the Vietnam war. McCain did eventually unendorse Trump in October 2016 after a video was published that captured Trump discussing groping women.