Depending where you sit on the political spectrum, an indictment against Hillary Clinton over her lingering email scandal is either as unavoidable as an eastern sunrise or the longest of long shots.

Clinton has apologized for having used a private, non-secure email account and home-based server while she was secretary of state from 2009 to 2013. She has said none of the emails sent or received via her clintonemail.com account was marked classified at the time, but several of the emails were upgraded to "top secret" status in January to prevent them from being released.

The FBI has been investigating whether classified information was mishandled as a result of the server snafu since last summer and is reportedly expected to be interviewing Clinton and some of her aides soon, fuelling speculation that charges could be pending.

Clinton, the front-runner in the Democratic race for the presidential nomination, has said she broke no laws and does not think she will be charged with a crime. But if she is, what will happen to her and her run for the U.S. presidency?

Will she be indicted?

The government does sometimes prosecute people who handle classified information outside of the mandated secure, government-controlled channels, but opinion is divided — often along party lines — on whether it will do so in Clinton's case.

In a recent opinion piece for the Wall Street Journal, former U.S. attorney general Michael Mukasey said criminal charges are justified because Clinton mishandled classified information — perhaps intentionally or out of negligence.

"It is nearly impossible to draw any conclusion other than that she knew enough to support a conviction at the least for mishandling classified information," Mukasey, who served under former Republican president George W. Bush, wrote on Jan. 21.

FBI director James Comey confirmed that the agency is conducting an investigation. into Clinton's use of a private email server. Recent media reports have suggested the agency will begin interviewing Clinton and her aides in the coming weeks. (Carolyn Kaster/Associated Press)

But left-leaning politicians and some academics disagree. Richard Lempert, a law professor at the University of Michigan and former chief scientist with the Department of Homeland Security, opined in a recent and lengthy piece for The American Prospect magazine that "there is no reason to think" Clinton committed any crimes with respect to her private email server.

That's in part, he wrote, because the heads of agencies like the State Department have "'considerable authority with respect to classified information" — including the power to declassify some material and to approve exceptions to how classified material is handled.

Could she still run if indicted?

Legally? Yes. There don't appear to be any U.S. federal laws that prevent someone under indictment — even for what could be an alleged violation of the Espionage Act — from running for the White House, according to Robert Shapiro, who teaches political science at Columbia University in New York.

Shapiro told CBC News that even if Clinton is indicted, she can still stay in the race.

"It certainly doesn't affect her running," he said.

But there's always a chance of complications. Prior to the Democratic National Convention in July, he says, there might be some "arcane" state laws that could interfere with, but not necessarily derail, the campaign.

"There could, conceivably, be state-related legal issues that get you into the weeds," he says. "But I suspect not."

Should she still run?

That's trickier. An indictment would cause strains within the Democratic Party and, if Clinton wins the nomination, make it harder to stay ahead of the Republicans. She and some of the party elite would have to weigh how it affects her electability.

Prior to the convention, an indictment could cost Clinton votes among delegates and perhaps hand the nomination to Bernie Sanders.

As of March 29, Clinton had 1,712 delegates on her side, to Sanders's 1,004. It takes 2,383 to secure the nomination, and 2,049 are still up for grabs.

But hundreds of her votes are from so-called super-delegates — high-ranked Democrats who have the luxury of changing their minds.

Bernie Sanders is trailing Clinton by about 700 delegates, but an indictment could change that if super-delegates who have so far supported Clinton switch their support. 'This can all shift,' says Robert Shapiro, political science professor at Columbia University in New York. (Pablo Martinez Monsivais/Associated Press)

"The super-delegates are virtually all committed to her," Shapiro says. (She has 469 to Sanders's 29.)

"But they could switch … this can all shift, and they could wind up being stuck with Sanders."

Polls suggest both Clinton and Sanders have a good chance of beating Republican frontrunner Donald Trump, but observers on both sides of the aisle agree a lot can change between now and November.

One thing is certain — an indictment would also hand a lot of free ammunition to whoever wins the Republican nomination.

Coming as it would from a Democratic-appointed attorney general, an indictment would also further weaken Clinton's claim that the seriousness of the email scandal has been exaggerated by Republicans for political purposes.

If not Hillary, who?

Sanders would not necessarily step up as the nominee if Clinton withdraws from the race. If she were to drop out prior to the convention, Shapiro says, the Democrats could alter their rules so that any delegates who had previously pledged their support for Clinton would be free to back someone else.

Clinton is not the only high-level cabinet member to have used a personal email account. One of her predecessors, Colin Powell, has admitted he used one, too, and didn't turn over emails to the State Department . (Kevin Lamarque/AP)

"They could go to anybody — pick your candidate," he said.

Names like Vice-President Joe Biden, Secretary of State John Kerry, Senator Elizabeth Warren and former VP Al Gore are already being tossed around.

But the last-minute arrival of any candidate from the party's inner circle would surely rankle Team Sanders.

His supporters "will go ballistic if he doesn't get the nomination," Shapiro said.

If Clinton were to withdraw after the convention, during the campaign proper, the party leaders would pick a replacement themselves, possibly from one of the above names.

That decision would happen quickly — and behind closed doors, said Shapiro.