FBI Director James Comey's big congressional hearing is today
The hearing will be the first time either Comey or Rogers have testified publicly since Trump was inaugurated. It comes just over two weeks after Trump tweeted, without presenting evidence, that Obama had Trump Tower's "wires tapped" during the presidential campaign.
Comey, under pressure from both parties for more information on Trump's wiretapping claims, held a classified briefing last Wednesday with Senate Judiciary Committee Chairman Chuck Grassley; the committee's ranking member, Dianne Feinstein; the Senate Intelligence Committee's top Democrat, Mark Warner; and Senate Minority Leader Chuck Schumer.
Grassley had threatened to withhold a vote for Rod Rosenstein to be deputy attorney general unless Comey gave him and the other senators their long-awaited briefing. The senators did not divulge details after the meeting.
The chairman of the House Intelligence Committee, Rep. Devin Nunes of California, said Sunday that the committee had not found any evidence to support Trump's claim that Obama had Trump Tower phones "tapped" before the 2016 election, and that he had obtained documents from the Justice Department confirming as much.
"Was there a physical wiretap of Trump Tower? No, there never was," said Nunes, a Republican. "The information we received Friday continues to lead us in that direction."
The president does not have the unilateral authority to order a wiretap on suspected foreign spies operating inside the US, experts say. Doing so would be a federal crime that would implicate career civil servants and necessitate a huge cover-up.
Rather, law-enforcement and intelligence agencies wishing to monitor signal intelligence they deem relevant to an investigation - in this case, suspected Russian interference in the 2016 election - must obtain what is known as a FISA warrant from the Foreign Intelligence Surveillance Court.
Nunes also denied on Sunday that a FISA warrant had been obtained.
"There was no FISA warrant I am aware of to tap Trump Tower," Nunes said.
It is still unclear, however, whether a warrant was ever granted to surveil foreign actors operating inside the US that might have been communicating with Trump aides.
Reports have suggested that communications between Trump's former national security adviser, Michael Flynn, and Russia's ambassador to the US, Sergey Kislyak, were picked up by US intelligence officials who had been eavesdropping on Kislyak - not on Flynn. Current and former US officials have also told several media outlets that they have intercepted communications between associates of Trump and Russian officials.
The House Intelligence Committee has asked the FBI, the CIA, and the NSA to give them a full list of people whose conversations may have been picked up in that kind of incidental surveillance. So far, only the NSA has "partially" complied, according to The Washington Post.
Nunes, and other Republicans, will likely focus much of their attention on Monday on grilling Comey about leaks from within the intelligence community to the press - an issue Comey has said is a top priority for the committee. Democrats, meanwhile, will likely hone in on what evidence the FBI has implicating Trump in Russia's election-related meddling.
Trump's explosive claims of wiretapping caused an international row last week when press secretary Sean Spicer read from unverified reports that said a British intelligence agency, the Government Communications Headquarters, or GCHQ, conspired with Obama to wiretap Trump.
The comment prompted a near-immediate reaction from GCHQ, which released a rare public statement categorically denying any involvement and calling the accusation "utterly ridiculous."
Trump doubled down on Monday morning, appearing to set the tone for the hearing, tweeting that "James Clapper and others stated that there is no evidence Potus colluded with Russia. This story is FAKE NEWS and everyone knows it!"
Trump then claimed that Democrats "made up and pushed the Russian story" to explain Democratic nominee Hillary Clinton's loss in the presidential election, and called on Congress and the US intelligence community to look into classified-information leaks.
Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, pushed back strongly.
"Mr. President, the Russians hacked our election and interfered. No one disputes this now, but you. This is what is called 'fact,'" Schiff tweeted in response to Trump. "As you will see during our hearing, Mr. President, there is no evidence Mr. Obama tapped your phones. This is what is called 'fiction.'"