Rep. Seth Moulton, a Democrat, is joining the ranks of lawmakers from both sides of the aisle condemning the sudden firing of FBI Director James Comey by President Donald Trump.

"President Trump fired the FBI Director less than 48 hours before he was scheduled to testify in front of the Senate Intelligence Committee ... suggesting a deep fear within the White House of the ongoing FBI investigation into President Trump's ties to Russia," Moulton said.

This is far worse than Nixon ... and this is how democracies become authoritarian regimes.

Moulton is calling for the appointment of a special prosecutor in the counterintelligence investigation into the Trump campaign's possible connections to Russia, but he says it won't be easy to accomplish with a Republican majority in Congress. 

"The problem is, a special independent prosecutor requires a law passed by Congress. It would have to get through a Republican Congress, and then if we didn't pass it with a two-thirds veto-proof margin, the president could actually veto that law," said Moulton.

Moulton says it's not a simple thing to appoint an independent prosecutor, but it's absolutely what we need to do.

"This is far worse than Nixon and this is how democracies become an authoritarian regimes," he said.

Moulton joined WGBH News' Morning Edition host Bob Seay, who asked him how Comey's firing compares to the Nixon era and Nixon's firing of Archibald Cox. Cox wasn't the FBI Director, but the independent prosecutor during the 1973 Watergate scandal, whose investigations led to the resignations of Nixon's U.S. Attorney General and Deputy Attorney General, and ultimately the resignation of President Richard Nixon.

Will Congress and the American people rise above partisan politics to do what's right for our country? We need an independent prosecutor, and it's time for our Congress to have an independent bi-partisan commission to figure out what's going on here.

Moulton says clearly the firing shows that President Trump has something to hide.

"We all know that is what's going on ... we learned last night that federal prosecutors have issued grand jury subpoenas to (former National Security Adviser) Michael Flynn's associates for his ties with Russia," Moulton said. "The administration has acted at every step of the way to try to block any investigation into its connections with Russia and repeatedly lied about those connections as well."

"Will Congress and the American people rise above partisan politics to do what's right for our country?" Moulton asked. "We need an independent prosecutor and it's time for our Congress to have an independent bi-partisan commission to figure out what's going on here."

President Trump has called the firing of Comey necessary to restore "public trust and confidence" in the FBI.

To listen to the entire interview with Congressman Seth Moulton and WGBH News' Bob Seay click on the audio player above.