Washington (CNN) FBI Director James Comey is once again finding himself at the center of a political firestorm.

And it's the last place the head of the nation's top law enforcement agency wants to be, especially with six years left in his 10-year term.

The Justice Department's inspector general announced Thursday he is probing the FBI's handling of the investigation into former Secretary of State Hillary Clinton's private email server during the 2016 presidential campaign.

The decision revived Democrats' arguments that Comey helped swing the election in Donald Trump's favor at the same time as he once again finds himself playing a central role in the most sensitive political story of the moment: briefing the President-elect on unsubstantiated allegations that Russia has compromising information about him.

The question now is whether Comey can withstand this latest round of political fire.

What is the Justice Department's inspector general probing?

The investigation will focus on how the FBI handled the Clinton email server investigation, particularly the agency's public disclosures about the investigation in the middle of the presidential election.

The review will examine whether Comey followed Justice Department and FBI policies when he took the unusual step of delivering a public statement explaining why his agency wouldn't pursue criminal charges against Clinton. It was in that public statement that Comey said Clinton was "extremely careless" in her handling of emails.

JUST WATCHED FBI director: Clinton 'extremely careless' with emails Replay More Videos ... MUST WATCH FBI director: Clinton 'extremely careless' with emails 00:51

The probe is also expected to focus on Comey's public letter to members of Congress less than two weeks before the election announcing that the FBI had discovered new emails potentially relevant to the investigation into Clinton's email server.

Soon after, the FBI announced it wasn't changing its July recommendation that Clinton not face criminal charges -- but Democrats have argued the damage against Clinton was already done.

So what are Democrats saying now?

Some are feeling vindicated -- but disappointed that it took so long for this kind of review to take place.

Brian Fallon, a former Clinton campaign spokesman, described the mood among Clinton staffers as "appreciative" of the news.

"A number of us that worked on the campaign were in touch yesterday in light of this news and all of us were appreciative of the fact that there's finally going to be an authoritative statement for the historical record about the inappropriateness of what happened here," Fallon said Friday on CNN's "New Day."

Fallon called Comey's actions "significantly questionable" and said Comey's letter to members of Congress notifying them of newly discovered emails that might be relevant to the Clinton server investigation -- plus Wikileaks' publication of apparently hacked emails of John Podesta and other Democratic Party members -- "combined for a perfect storm of a bad swirl of information."

Even Corey Lewandowski, Trump's former campaign manager, cited Comey's letter as a factor that helped the Republican nominee win, saying "with 11 days to go in this election cycle, something amazing happened" in a post-election speech.

Could this prompt Comey to resign?

He hasn't indicated that he has any plans to do so. But the inspector general's review will certainly ensure that the question continues to be raised.

Comey, for his part, welcomed the review and said "everyone will benefit from thoughtful evaluation and transparency regarding this matter."

But it's not all that's amplifying the drumbeat demanding his resignation.

What are the other political firestorms engulfing the FBI director?

Testifying before the Senate Intelligence Committee this week, Comey laid bare the inconsistencies of his responses to various investigations.

JUST WATCHED James Comey: Russia tried to hack RNC Replay More Videos ... MUST WATCH James Comey: Russia tried to hack RNC 01:07

Comey declined to confirm or debunk reports that the FBI has been probing potential contacts between the Trump campaign and the Russian government, saying "especially in a public forum we never confirm or deny a pending investigation."

Sen. Angus King, an independent who caucuses with Democrats, seized on the fact the Comey was now mum when he acted very differently in the Clinton email server investigation.

"The irony of your making that statement here, I cannot avoid," King said incredulously.

Comey reiterated the investigation into Clinton's email server was closed when he spoke about it..

What's the reaction been to that?

It prompted the Wall Street Journal's conservative editorial board to call for Comey's resignation, citing a "long history of apparently political decisions" that have hit both sides of the political aisle.

"If the FBI director has demonstrated anything in the last year, it's that he has lost the trust of nearly everyone in Washington, along with every American who believes the FBI must maintain its reputation as a politically impartial federal agency," read the Journal's editorial.

What about his involvement in briefing Trump on unsubstantiated information that Russians have compromising information about him?

It wasn't Comey's decision alone to provide Trump with a two-page summary of an unverified report compiled by a former British intelligence official whose Russian sources claimed to have compromising personal and financial information about the incoming president.

But Comey was tapped to brief Trump directly on the allegations after the top four intelligence chiefs briefed Trump on Russian hacking during the election last Friday, according to multiple US officials briefed on the matter.

The same sources tell CNN Comey briefed Trump one-on-one about the sensitive and unsubstantiated allegations.

JUST WATCHED Explaining the Trump intel memo controversy Replay More Videos ... MUST WATCH Explaining the Trump intel memo controversy 15:23

The decision to brief Trump -- and provide the same documents to President Barack Obama -- has come under fire from some.

Mike Morell, former CIA acting director, said he was "a bit surprised that our intelligence community would take a private document and summarize it for the President and President-elect if they didn't know anything about the credibility of the information in it."

Morell said the briefing appeared to be "unprecedented."

Trump, for his part, has panned the information as "totally made-up facts by sleazebag political operatives."