Sen. John McCain made a Sunday morning appearance with CNN's Jake Tapper, who asked the Arizona Republican whether he's concerned about the "constant barrage of conspiracy theories" coming from President Donald Trump.

McCain again came out and said Trump either needs to retract his comments that former President Barack Obama ordered a wiretap on his phones at Trump Tower or provide some proof. Trump has been quiet about his wiretap allegation since tweeting it more than one week ago.

Tapper asked McCain that if there is no proof for what the president said, “should President Trump take back his charge and apologize to President Obama and to the American people?”

McCain answered:

"Well, President Trump has to provide the American people, not just the intelligence community, but the American people with evidence that his predecessor,  former President of the United States, was guilty of breaking the law, because our director of national intelligence, Gen. Clapper, testified that there is absolutely no truth to that allegation."

He continued: “The president has one of two choices: Either retract or to provide the information the American people deserve, because if his predecessor violated the law, President Obama violated the law, we’ve got a serious issue here, to say the least.”

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Tapper then said he has heard of no one — from the FBI, other intelligence agencies, Vice President Mike Pence, Press Secretary Sean Spicer or others in Trump’s orbit — who claims to have any evidence supporting the wiretapping allegations.

Tapper asked McCain point blank: “Do you have any reason to believe this charge is true?”

McCain responded:

"I have no reason to believe that the charge is true, but I also believe that the president of the United States could clear this up in a minute. All he has to do is pick up the phone, call the director of the CIA, director of national intelligence and say, 'OK, what happened?' Because they certainly should know whether the former president of the United States was wiretapping Trump Tower."

Tapper wrapped up the interview by asking McCain whether he’s concerned about the conspiracy theories coming from Trump.

McCain replied, “The president obviously has a unique style.”