Michael Cohen delivers searing indictment of President Trump as a person: ANALYSIS Cohen: I can't "change the past, but I can do right by the American people."

The scene was cinematic and surreal, a tragicomedy that could only be imagined in the era of President Donald Trump.

A quiet and seemingly shrunken Michael Cohen on Wednesday laid out a case against his former longtime boss in front of a congressional committee on Capitol Hill, just weeks before the former "fixer" heads to prison for lying to Congress.

“I may not be able to change the past, but I can do right by the American people,” Cohen said.

Cohen delivered a searing indictment of Trump as a person.

Cohen, the ultimate loyalist, was displaying supreme and total disloyalty; he called the president “a racist,” “a conman” and “a cheat.”

The man who once proudly labeled Trump “the Godfather of politics” portrayed the president as a smalltime mob boss – squelching on debts, directing shady financial schemes, and ultimately labeling a turncoat as a “rat.”

Cohen, who just a day earlier was disbarred as a lawyer, brought documents as well as anecdotes to buttress his case. It’s a case weakened by his admissions of previous lies in front of Congress, though strengthened by other developments even since his public break with the president.

Taken as a whole, the material Cohen offered knowledge of is explosive – suggesting crimes and cover-ups, and hinted of campaign cooperation with Russia.

Democrats put a particular focus on potential campaign-finance violations related to payoffs intended to silence an alleged Trump mistress, Stormy Daniels, with Cohen producing checks signed by the president and his son that he claims were used for those purposes.

Cohen also said he was aware of another “wrongdoing or illegal act” that is being investigated by prosecutors in the Southern District of New York, though he did not elaborate. He also said something he discussed with the president in their last communication with each other is currently under investigation as well.

In a twist on the expected narrative, Cohen knocked down several narratives that would have made the president look worse and rebutted reporting that Trump directly told him to lie to Congress about a proposed project in Moscow.

The biggest potential damage from the extraordinary day appeared likely to threaten Trump as a person far more than Trump as a president. Cohen described small episodes – attempts to prevent his SAT scores and college transcripts from being released publicly, and ensuring that a portrait of himself would auction at a high price – that cast Trump as cynical, manipulative, and deeply dishonest.

That, however, fits with plenty of popular perceptions of Trump. He won the presidency in spite of – if not because of – character traits much like those, and those traits were long exacerbated by his association with individuals like Cohen. Pressed by a Democrat on the committee, Cohen estimated that he issued some 500 threats on Trump’s behalf during his decade working for him.

The lies Cohen admitted to telling were, for the most part, lies to protect Trump. Republicans on the committee spent the bulk of their time trashing Cohen as an untrustworthy felon, rather than explaining or defending the president’s character or actions.

The oversight committee’s top Republican, Ohio Rep. Jim Jordan, suggested that Cohen held a grudge against Trump after being passed over for a White House job. Rep. Mark Meadows, R-N.C., accused Cohen of misleading the committee about his previous foreign contracts, and several members suggested that Cohen is seeking to turn his fame into a book or TV deal.

"No one should ever listen to you and give you credibility," said Rep. Paul Gosar, R-Ariz. Gosar featured a poster board with Cohen’s face on it, reading, “Liar, liar, pants on fire.”

The time spent attacking Cohen instead of lining up behind Trump wasn’t lost on former Gov. Chris Christie, a Trump ally who is now an ABC News contributor.

“There hasn't been one Republican yet who's tried to defend the president on the substance,” Christie told ABC’s George Stephanopoulos, midway through the testimony. “I think that's something that should be concerning to the White House.”

The day, like so many before it, seemed unlikely to shift perceptions of the president. More seeds were planted for further investigations that will spring out of the Democratic-controlled committees on Capitol Hill, and hints came of what New York-based prosecutors are still working on.

Cohen took the incoming fairly well, seldom growing testy with Republicans who questioned his motives. In one moment that broke through the noise, he offered himself up as a cautionary tale to a GOP questioner.

"I did the same thing that you're doing now for 10 years,” Cohen said. “I can only warn people — the more people that follow Mr. Trump, as I did blindly, are going to suffer the same consequences as I did.”