Senate Armed Services Committee chairman John McCain has called for President Trump to either prove his claim that President Barack Obama tapped the phones in Trump Tower during last year's election campaign or drop the accusation.
"The president has one of two choices, either retract or provide the information that the American people deserve," McCain said in an interview on CNN's State of the Union. "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 is one of several top lawmakers in Congress to call on Trump to provide evidence of his unsubstantiated claim that Obama ordered Trump's communications monitored. The senator's call for more information follows a request from two leading members of the Senate Judiciary Committee for "copies of any warrant applications and court orders - redacted as necessary ... related to wiretaps of President Trump, the Trump Campaign, or Trump Tower."
South Carolina Senator Lindsey O. Graham and Rhode Island Senator Sheldon Whitehouse formally requested the information last week in a letter to FBI director James B. Comey and acting deputy attorney-general Dana Boente. Trump administration officials have not provided any evidence to back up the President's claim from earlier this month.
McCain avoided directly criticising Trump for using Twitter to spread unverified information, but the senator said a serious charge, such as accusing a former President of illegal wiretapping, should not be handled lightly.
"If the allegation is left out there, it undermines the confidence the American people have in the entire way that the Government does business," McCain said.
Several lawmakers, including McCain and Senate Rules Committee chairman Roy Blunt have pointed out that Trump could directly ask intelligence officials to corroborate his claim but instead has asked Congress to investigate.
"The President actually could himself ask that question," Blunt said on Fox News' Sunday Morning Futures.
Not all Republicans have been so quick to put the burden of proof on Trump. Arkansas Senator Tom Cotton agreed with Trump that Congress should take control of the investigation to safeguard sensitive intelligence.
"President Trump said last weekend that he wanted the intelligence committees in the Senate and the House to take up this matter as part of a broader inquiry into Russia's activities in our political system last year. We're going to do that," Cotton today said on ABC's This Week.
"Through a deliberate and careful process of examining all the intelligence at issue here, and then determining with the executive branch what we can declassify, I think the intelligence committees are in the best position to make those decisions," the senator added.