Obama categorically denied Trump’s claim.

Republican South Carolina senator Lindsey Graham summed up the implication of Trump’s accusations best.

Essentially, if Trump’s claim is accurate, and the Obama administration did act unlawfully, this could be the biggest scandal since Watergate, said Graham. Conversely, if Obama lawfully obtained a warrant to tap the Trump campaign, it would be an equally momentous scandal.

“I would be very worried, if in fact, the Obama administration was able to obtain a warrant lawfully about Trump campaign activity with foreign governments. So it’s my job as a US senator to get to the bottom of this,” said Graham, addressing an audience at a town hall at Clemson University shortly after Trump’s tweetstorm, to laughter and jeers from the audience.

A former senior intelligence official told the Washington Post, “If that were the case by some chance, that means that a federal judge would have found that there was either probably cause that [Trump] had committed a crime or was an agent of a foreign power.”

The same official said the claim was “highly unlikely” and “unthinkable.”

Trump offered no proof of his claims, though it looks like he may have been influenced by conservative media. Earlier this week, radio talk show host Mark Levin said that Obama used “police state” tactics to keep an eye on Trump. Levin’s remarks were then recycled by the right wing news outlet, Breitbart, which broke down Levin’s claims point-by-point.

Democrat leader, Nancy Pelosi, among others, called for a full investigation of Trump’s accusations, while California’s lieutenant governor Gavin Newsom suggested the tweets implied an investigation was already in progress and “Trump just declassified it or shared classified information on Twitter.”

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