(The Hill) – It’s a controversy that erupted out of nowhere to dominate the headlines.

On Monday, CBS News revealed that documents marked as classified had been discovered in an office used by President Biden after he left office as vice president.

Subsequent days brought disclosures of a second batch of documents discovered in the garage of Biden’s Wilmington, Del., home; one more sheet of paper found elsewhere in the residence; and then an admission that an additional five pages bearing classified markings had been found.

The revelations have pushed Biden and the White House onto the defensive. They’ve also lifted Republicans’ political spirits after the bruising fight to elect Rep. Kevin McCarthy (R-Calif.) as Speaker.

There are a number of unanswered questions. Here are five of the biggest.

Why wasn’t the public told sooner?

The timeline regarding the documents is one of the most mysterious — and politically damaging — elements of the controversy.

The first batch of documents was uncovered on Nov. 2 in Biden’s old office at a University of Pennsylvania facility in Washington.

This appears to have precipitated a search of other locations, which led to the revelation of the Wilmington garage documents by Dec. 20.

Another document came to light only on Wednesday.

But hopes among Biden supporters that this would be the final revelation were dashed by a Saturday statement from White House lawyer Richard Sauber, noting that there were “five additional pages with classified markings” uncovered by him on Thursday.

Crucially, there was a long stretch when the whole issue remained unknown to the public. The first CBS story came almost 10 weeks after the initial discovery.

Politically speaking, the problem is not only the passage of time in itself. It’s that the first documents came to light six days before the midterm elections.

Republicans including incoming House Judiciary Committee Chairman Jim Jordan (R-Ohio) have seized on that point, insisting that the American people had a right to know about the matter when they were on the cusp of casting their ballots.

Finally, on Saturday, the president’s personal attorney, Bob Bauer, made a counterargument.

In a statement, Bauer asserted that “limitations necessary to protect the investigation’s integrity” had militated against public disclosure.

Much will depend on whether voters buy that argument or see it as a convenient excuse.

What did Biden know and when did he know it?

The president has said that he was surprised to learn about the documents.

Biden also contends that he does not know what exactly they contain — and says that his lawyers have advised him against asking.

There was one further, odd comment in an exchange with Peter Doocy of Fox News. 

Doocy asked Biden what he was “thinking” by having classified documents “next to your Corvette.” 

Biden shot back that he would speak more about the matter soon and added, “By the way, my Corvette is in a locked garage. OK? So it’s not like it’s sitting out in the street.” 

The apparent implication — that measures sufficient to secure a sports car would also be adequate for classified documents — was not helpful to Biden’s cause.

In any event, Biden was, at the very least, apprised of what was going on with the documents as it was happening. 

White House press secretary Karine Jean-Pierre, who came under sustained pressure from reporters at several briefings this week, said that Biden “has been kept informed by his counsel throughout this process.”

The president is sure to face more questions soon on the specifics.

What is in the documents?

Perhaps the biggest question of all.

So far, Biden’s defenders have taken heart from the fact that the whole matter seems to focus on a modest number of documents. 

The initial batch, in the University of Pennsylvania office, reportedly numbers less than a dozen.

CBS News reported early Saturday that “the total number of known documents marked classified is roughly 20, between the two locations.” This count came before Sauber’s statement referencing the five additional pages, however.

Much will hinge on the sensitivity of the information contained in the documents.

CNN reported on Tuesday that some documents from the office included intelligence and briefing materials on “topics including Ukraine, Iran and the United Kingdom.”

That seems bad news for Biden. 

If the documents open him up to the accusation of jeopardizing the national security of the United States or allies such as the U.K., it would be potentially grave.

How broad does the special counsel’s probe become?

Attorney General Merrick Garland has appointed Robert Hur as special counsel to look into the matter. 

Garland has said that a special counsel is necessary to reassure Americans about the probity of the investigation.

But presidents dislike special counsels for a reason — they are typically given very wide-ranging powers.

The order appointing Hur notes that he can look into the documents and “any matters that … may arise directly” from them.

No one is expecting Hur’s probe to resemble the most famous special counsel investigation of recent years, headed by Robert Mueller. But by way of illustration of a special counsel’s powers, Mueller’s probe into allegations of collusion between Russia and former President Trump’s 2016 campaign lasted from 2017 to 2019 and involved the issuance of around 2,800 subpoenas.

It would be amazing if Hur’s probe lasted more than a fraction of that time. 

But there is always the possibility that the special counsel, who was nominated by Trump to be the U.S. attorney for Maryland, could uncover new and damaging information. 

Will voters grasp the difference between his case and Trump’s?

Republicans wasted no time in using the Biden matter to try to neutralize criticisms of Trump for his conduct in relation to documents marked as classified and discovered at Mar-a-Lago.

The comparison works at a headline level: Both men are now subject to investigation for their handling of classified documents.

But there is at least one huge difference. 

In Biden’s case, the documents were promptly returned to the National Archives upon being discovered.

In Trump’s case, the fate of those documents was subject to a long battle. 

The National Archives requested documents that it believed were in Trump’s possession in May 2021. The FBI did not raid Mar-a-Lago, search warrant in hand, until August 2022. 

During the intervening 15 months, there appear to have been two occasions on which the Trump team said or implied it was handing over all relevant documents while not actually doing so.

It’s this chain of events that many legal experts believe puts Trump at real risk of obstruction charges from the special counsel in his case, Jack Smith.

Nothing comparable, so far, has been discovered in Biden’s case.

But politically, much will depend upon whether the White House can persuade the American public that Biden or his staff committed an inadvertent error, whereas Trump was involved in something more nefarious.

The distinction is crucial, but will voters accept it?