President Trump and his top aides are responding to an intense controversy over last week's firing of FBI director James Comey, an outcry that will continue for weeks and perhaps longer. Replacing the FBI leader before a 10-year term ends is rare, though allowed. The main issue is whether Trump did so in an effort to hinder or end an expanding bureau inquiry into possible 2016 presidential election mischief by Russia. Agents also explore reported ties between Trump campaign figures and the Russian government – something the president calls "the witch hunt," as he tweeted Friday. Trump feels claims of collusion with Moscow are politically motivated, tweeting two days after he sacked Comey: "Russia must be laughing up their sleeves watching as the U.S. tears itself apart over a Democrat EXCUSE for losing the election."

But on Capitol Hill, Trump's abrupt move seems to embolden the Republican-led Senate Intelligence Committee investigating Russia's election interference and the president's associates. Senators subpoenaed sworn testimony from fired national security adviser Michael Flynn at an upcoming hearing, one of several expected in Congress. Some Democrats also call for the Justice Department to name an independent prosecutor to consider any lawbreaking, such as obstruction of justice. (A 1973 special prosecutor during Richard Nixon's presidency looked into a break-in at Democratic National Committee offices in the Watergate building, as well as an official cover-up that followed. Incriminating evidence led Nixon to resign in 1974.)

The political sensitivity of the top FBI job led Congress in 1976 to set the term at 10 years to give the appointee independence. A president still can remove the director, but that happened just once before. President Clinton dismissed William Sessions in 1993 for ethical lapses, which didn't cause an uproar. This time, blowback from Comey's dismissal leads White House aides and Trump to issue several explanations of why he acted, creating contradictions and more questions. The politically inexperienced president’s visible anger and erratic tweets prompted a reporter to ask press secretary Sean Spicer on Friday if the president is "out of control." The spokesman shot back "That's, frankly, offensive."

President says: "James Comey better hope that there are no ‘tapes’ of our conversations before he starts leaking to the press!" – May 12 tweet

Editorial says: "Mr. Trump apparently tried and failed to extract a vow of loyalty from Mr. Comey. . . . To Mr. Trump, 'loyalty' meant abandoning an investigation into foreign interference in the last election." –The New York Times

Legal analyst says: "Trump's short-circuiting of the [Russian election meddling probe, with Comey's dismissal, is a grave abuse of presidential power." – Jeffrey Toobin, CNN commentator, author and New Yorker magazine writer