For Democrats, former FBI Director James Comey will return to Capitol Hill like a conquering hero.

When Comey testifies before the Senate Intelligence Committee about his conversations with President Trump before he was fired from the bureau, he will be hailed as a brave public servant who spoke truth to power as a corrupt White House tried to shut down the Russia probe.

Sen. Martin Heinrich, D-N.M., called Comey's opening statement, which was published Wednesday, "devastating." Rep. Adam Schiff, D-Calif., the ranking member on the House Intelligence Committee, asked if Comey's refusal to pledge loyalty to the president cost him his job.

"Donald Trump appears to have obstructed justice," said Sen. Edward Markey, D-Mass.

Not long ago, however, Comey was viewed as having interfered in the 2016 presidential election to the Democrats' detriment to an event greater extent than the Russians.

"Remember, Comey was more than happy to talk about my emails, but he wouldn't talk about the investigation of the Russians," Hillary Clinton recently told a tech conference. "So people went to vote on November 8th having no idea that there was an active counter-intelligence investigation going on of the Trump campaign."

Even after the hacking of John Podesta, WikiLeaks and all the other Russian meddling in the election, Clinton declared at an earlier New York City event, "If the election had been on October 27, I would be your president."

Senate Minority Leader Chuck Schumer, D-N.Y., was "appalled" by the pre-election letter from Comey to Congress announcing he was reopening the investigation into Clinton's emails. "I do not have confidence in him any longer," Schumer said.

Schumer's predecessor as Senate minority leader, then Sen. Harry Reid, D-Nev., accused Comey of violating federal law. "I am writing to inform you that my office has determined that these actions may violate the Hatch Act, which bars FBI officials from using their official authority to influence an election," Reid wrote in a letter.

"My confidence in the FBI director's ability to lead this agency has been shaken," said Rep. Hank Johnson, D-Ga. "The FBI director has no credibility," concurred Rep. Maxine Waters, D-Calif.

"Maybe he's not in the right job," offered House Minority Leader Nancy Pelosi, D-Calif. "He embarrassed this nation, he possibly influenced the outcome of a presidential election, and he should not hold any position of trust, whatsoever, in our government," protested Rep. G.K. Butterfield, D-N.C, who previously chaired the Congressional Black Caucus.

Rep. Steve Cohen, D-Tenn., penned a column calling on Comey to resign his position as director of the FBI. "The criticism of Director Comey is strongly bipartisan and has come from many experts in the field of justice," Cohen wrote in November.

The last time Comey appeared before Congress, in fact, he angered Democrats by badly misstating the number of emails key Clinton aide Huma Abedin forwarded to her husband, the disgraced former Congressman Anthony Weiner, D-N.Y.

"The misstatement also raises new questions about Comey's factual grasp on a matter of huge importance," wrote the Atlantic's David A. Graham. "If he was confused about the basic technological processes involved in the emails — and even if his staff was better informed — how reliable was his decision-making process at that crucial juncture in October?"

All this makes one bewildered comment from the president about the Democratic backlash more understandable. "I guess I was a little bit surprised, because all of the Democrats, I mean, they hated Jim Comey," Trump told Fox News.

None of this makes it any more plausible that Trump fired Comey for mishandling the investigation into "lock her up" Clinton's emails. Trump undercut this rationale himself when he repeatedly mentioned Russia in the context of Comey's dismissal.

Neither did Trump cover himself in glory if his actual words and deeds were exactly as described in Comey's surprisingly detailed opening statement, which was released a day ahead of his Thursday congressional testimony.

But Trump often seems more bumbling than devious in Comey's portrayal, and key portions of the testimony appear to support the president's protestations that he had at least been told he was never under investigation on Russia-related matters.

On Thursday, Democrats will rely heavily on Comey's judgment while evaluating the president of the United States.

That's not something they would have been willing to do on Oct. 28.