Former FBI director James B. Comey testified about his interactions with President Trump before the Senate Intelligence Committee June 8. Here are key moments. (Sarah Parnass/The Washington Post)

James Comey just can't seem to stop haunting President Trump. Trump fired Comey as FBI director a few weeks ago, and now Comey is hours away from testifying to Congress that Trump may have tried to interfere in the FBI's investigation into Russia and politicize the FBI.

Comey is known as a drama-averse guy, and this is as dramatic as it gets. Comey is likely very aware he is jumping into a major showdown with the president. So what's in it for him?

We tried our best to get inside Comey's head and run down the pros and cons of sharing what he knows with Congress.

Pro: His reputation is at stake

At the June 8 Senate Intelligence Committee hearing, former FBI director James Comey said the Trump administration "chose to defame" him and the FBI after he was fired. (Video: Reuters)

Trump said he fired Comey for doing a bad job, then called him a “nut job” to the Russians.

That is presumably not how Comey wanted to go out.

Comey spent more than a decade in high-profile public-service jobs cultivating a reputation as a competent, aggressively nonpartisan public servant. Two presidents from different parties appointed him to top law enforcement jobs. The Fix's Aaron Blake reports that Comey's reputation in law enforcement was as a guy who genuinely tried to do the right thing but occasionally made mistakes.

[LIVE UPDATING: How cable news networks are reacting to Comey’s hearing]

Now, Comey has a chance to tell his side of his story — and try to clear his name.

“The idea that [people like Comey] care about their reputations for public service and probity,” said Dartmouth College political-science professor Linda Fowler, “is maybe catching the administration by surprise.”

Con: It could turn into a Comey-vs.-Trump war of words

If we know one thing about how Trump reacts to controversy, it's that when he's poked by a stick, he swings back with the forest.

And Comey now represents the biggest confrontation to the president's reputation yet. His seven-page testimony about his conversations with Trump make clear that Comey was concerned the president tried to interfere in the FBI's investigation:

[Graphic: The road to testimony: What we know about Comey’s interactions with Trump]

“'I hope you can see your way clear to letting this go, to letting Flynn go,'" Comey recalled Trump telling him about his now-fired national security adviser, Michael Flynn. "'He is a good guy. I hope you can let this go.” I replied only that 'he is a good guy.'"

Was this obstruction of justice? It's a question Congress and special counsel Robert Mueller will have to ask. Really, many of the existential threats to Trump's presidency can be traced back to Comey:  The Washington Post reported that Trump also asked other top intelligence officials to interfere and/or deny the existence of any evidence of Trump campaign's collusion with Russia -- all to counter Comey's congressional testimony that there was enough of a suspicion to warrant an investigation.

And Trump doesn't play nice with people he perceives as his enemies. Remember when he retweeted an unflattering picture of a primary opponent's wife during the campaign?

Pro: There are a lot of questions he can help clear up

Since Comey's firing, there are way more questions than answers. Such as:

  • Did the president try to interfere in an independent investigation into his campaign aides?
  • If so, did the president knowingly obstruct justice?
  • And what did the president's top advisers (such as Vice President Pence) know?

If, as Comey has testified in the past, the truth matters more than any one person's political fortunes, then sharing what he knows with Congress has its upsides on principle.

(The Post's Devlin Barrett reports Comey isn't expected to shed any new light on the ongoing FBI investigation but rather will focus on his personal conversations with the president.)

Con: Comey better have his facts straight, or else

The Trump administration is excellent at picking out a factual mistake and trying to discredit everything else that person — or the group that person belongs to — says or does.

And the last time Comey testified to Congress, he got at least one key fact wrong. As part of his justification for resurfacing the FBI's Hillary Clinton email investigation 11 days before the election, Comey said investigators found “hundreds and thousands” of Clinton emails on disgraced former congressman Anthony Weiner's computer. (Weiner is the estranged husband of top Clinton aide Huma Abedin.)

The FBI had to amend the record of Comey's testimony the next day to say the number of Clinton emails on Weiner's computer was much smaller and it wasn't a “regular practice,” as Comey testified.

Pro: Comey is good at congressional testimony. Really good.

Before the 2016 campaign, Comey's most famous moment came in the hot seat in Congress.

In 2007, a Democratic Congress was investigating the George W. Bush Justice Department. Lawmakers called in Comey, who had recently finished a job as the No. 2 official in the department, for what they thought would be a routine testimony.

But Comey had a story up his sleeve.

It was 2004. Attorney General John Ashcroft was sick in the hospital. Comey, then Ashcroft's deputy, got a call that Bush officials were on their way to the hospital to persuade Ashcroft to sign on the dotted line and reauthorize Bush's controversial domestic surveillance program, which the Justice Department had just said was illegal.

Sirens blaring, Comey said he raced to Ashcroft's hospital room, arriving minutes before the White House officials did. Ashcroft didn't authorize the program.

The Post's Paul Kane said Comey's story was perhaps the most riveting 20 minutes of congressional testimony ever.

And it was completely unexpected for most in the room.

“Comey is pretty good at stage-managing congressional testimony,” said Cornell Law professor Josh Chafetz.

This time, we are fully expecting bombshells from Comey. (Just his opening testimony is jaw-dropping.) If he wants to deliver them, well, he knows how. And by agreeing to testify, it looks as if he's decided it's to his benefit to do so.