Some observers are comparing President Donald Trump's decision to fire FBI Director James Comey to the Watergate crisis.
Experts even suggest that the firing could turn out to be bigger than Watergate, depending on the reasoning behind Trump's decision, Business Insider reports.
"President Trump's firing of Director Comey sets a deeply alarming precedent as multiple investigations into possible Trump campaign or administration collusion with Russia remain ongoing, including an FBI investigation," Democratic Sen. Edward Markey of Massachusetts said in a statement.
"This episode is disturbingly reminiscent of the Saturday Night Massacre during the Watergate scandal and the national turmoil that it caused," he added.
The "Saturday Night Massacre" refers to President Richard Nixon's decision during the Watergate crisis to fire the special prosecutor in the Watergate investigation, The Washington Post reports. This resulted in the attorney general and deputy attorney general resigning in protest.
Democratic Sen. Richard Blumenthal of Connecticut went further, arguing that "not since Watergate have our legal systems been so threatened and our faith in the independence and integrity of those systems so shaken."
Former CIA officer and national security expert Glenn Carle referred to Trump's removal of the FBI director as "borderline betrayal."
The official explanation, that Comey was fired due to his mishandling of the probe into Hillary Clinton's emails, was dismissed by Fox News host Charles Krauthammer.
"If that was so offensive to the Trump administration, what you would have done during the transition is you would have spoken to Comey and said, 'We're going to let you go'," he said.
Richard Painter, who served as chief ethics lawyer under President George W. Bush, raised concerns about Trump taking action against someone who was leading an investigation into his administration's alleged ties with Russia.
"It's a lot worse than Watergate," he added. "Watergate was a third-rate burglary. It was purely domestic in nature. This situation involves Russian espionage, and we've got to find out who is collaborating."
The situation has prompted several people, including some Senate Democrats, to call for a special prosecutor to be appointed to guarantee the independence of the investigation over Trump's alleged Russian ties.
in 1973, Attorney General Elliott Richardson appointed Archibald Cox as special prosecutor in the Watergate affair. Cox subpoenaed audio recordings from the Oval Office, but Nixon fought this in the courts.
However, law professor Josh Chafetz pointed out that a special prosecutor may not resolve the worries of Trump's critics.
"The special prosecutor's agreement with the attorney general may specify certain types of independence but, at the end of the day, the prosecutor works for the Department of Justice and can be fired by the attorney general or the president," Chafetz told The Washington post.