“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,” McCain told host Jake Tapper on CNN’s “State of the Union.” “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.”

McCain said Trump should provide the American people with any evidence he has to support his claim, which seemingly emerged from right-wing media reports rather than any intelligence.

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