"If it's corrupt and he believes there to be corruption, he has every right to withhold aid," the Republican senator said.
"I think it's really regrettable that now the president and his supporters and others are advocating his [or her] unmasking," the former Director of National Intelligence James Clapper told CNN.
Walter Shaub, an ex-director of the Office for Government Ethics, said the Kentucky senator would be committing "one of the most shameful breaches a legislator could commit."
"He didn't want to break the law directly on national television, so he requested that you [the media] do it," Senator Angus King said.
The president also joked that he could stay in office for a further 21 years, prompting cheers from the crowd.
Speaking at a Trump rally in Kentucky, Sen. Rand Paul claimed to know the identity of the whistleblower and called on the media to unmask them.
A pair of New Yorkers ridiculed Kentucky GOP Senator Rand Paul in a California restaurant Friday, with a woman declaring she won't deal with his "Republican bulls**t."
"I mean, giddy-up, let's do it," Stephanie Ruhle suggested.
"The top one percent in our country pay 40 percent." Paul said he was citing IRS statistics when making the claim.
The White House has been considering how to respond to the weekend's attacks on Saudi oil infrastructure, which both Washington and Riyadh are blaming on Iran.
"No wonder he ripped his toupee off": Ilhan Omar responded to Rand Paul's "ungrateful to America" comments by sharing a Tom Arnold tweet mocking the Kentucky Republican.
"I have a mind to call him a scallawag and a ragamuffin," the comedian joked earlier in the day about GOP Senator Rand Paul.
"Shame on him. That's not even about politics anymore. We're talking about being a good human being," John Feal said.
The Republican from Kentucky argued that it sends a "bad signal" as the Trump administration simultaneously tries to push through a new free trade agreement with Canada and Mexico.
Graham suggested that his legal advice would be to "call it a day" and avoid testifying in front of the Senate Intelligence Committee again.
"[Trump] doesn't seem to understand that a fundamental aspect of his job is to try to make us a more perfect union," the congressman said.
"My position is the same that it's always been," GOP Senator Rand Paul told Newsweek. "I'm both for vaccines and freedom. I think you can have both."
Kentucky Senator Rand Paul's decision not to back President Donald Trump's national emergency exposed a growing rift in the Republican Party.
"In fact, I think the president's own picks to the Supreme Court may rebuke him on this," the Republican senator said.
The attack against the Republican was not politically motivated.
Paul said the president believes "we've been at war too long and in too many places."
While the gender wage gap is minimal among new staffers of both parties, reflecting equitable starting salaries, the gap widens over time.
"It just like a lot of other things we've done in Washington," the Republican senator from Kentucky argued. "We've overcriminalized campaign finance."
Rand Paul calls on Trump administration to halt sale of U.S. technology firm to Broadcom, which recently moved from Singapore to California.
It would not be the first time Trump has acted on an idea that Paul, a close friend and ally to the president, has suggested to him.