The federal grand jury that has been hearing evidence in the Justice Department’s investigation of former President Donald Trump’s handling of classified documents is expected to meet again this coming week in Washington, according to multiple people familiar with the investigation. Prosecutors working for Special Counsel Jack Smith have been presenting the grand jury with evidence and witness testimony for months, but activity appeared to have slowed in recent weeks based on observations at the courthouse and sources. It’s unclear whether prosecutors are prepared to seek an indictment at this point. The Justice Department would not comment on the status of the investigation. Based on reporting from NBC News and other outlets, prosecutors face two central legal questions: 1) Did Trump wrongfully retain classified documents after he left the White House? 2) Did he later obstruct the government’s efforts to retrieve them?If Smith decides to indict Trump, it would be the first time a former president has been charged with a federal crime. Though Trump has already been charged in New York with state crimes related to hush money payments, the cases differ dramatically.Trump maintains that he has broken no laws and continues to lambast Smith and the Justice Department, dismissing the investigation as a politically motivated smear campaign. Here’s what we know and what we don’t know, and what to watch for as this unprecedented legal case unfolds.What are the facts?In June 2022, federal agents traveled to the former president’s home in Florida to retrieve documents from his time in the White House, at least some of which they believed to be classified. Trump’s attorneys turned over 38 classified materials to authorities, and certified in writing that they’d done a diligent search.After visiting Mar-a-Lago and obtained evidence that additional classified documents had not been returned, Justice Department officials obtained a search warrant from a judge and FBI agents searched Mar-a-Lago in August 2022. In total, the DOJ recovered more than 300 documents with classified markings.Trump’s attorneys previewed their defense case in a letter to Congress this year, writing that the documents ended up in Florida because White House staff had “simply swept all documents from the President’s desk and other areas into boxes.” But it’s unclear whether Smith’s probe has unearthed evidence to the contrary.What crimes could Trump be charged with?Clues about what precise crime or crimes Smith has been investigating can be found in court filings, including the search warrant and an accompanying affidavit submitted by the DOJ. There are two basic categories: 1) crimes about the handling of classified documents, and 2) crimes about obstructing investigators from retrieving those materials. Prosecutors cited the Espionage Act, which conjures up an image of someone acting as a spy for a foreign country. But the statute, enacted after World War I, is broader. It criminalizes anyone with “unauthorized possession” of “national defense” material who “willfully” retains it. A string of court decisions has concluded that even if a document isn’t technically “classified,” someone can be charged under the law, so long as the information is “closely held” and the information would be useful to US adversaries.Justice Department attorneys also raised the prospect of an obstruction-related crime in court filings. But that law only applies if prosecutors can show that Trump’s intent was to “impede, obstruct, or influence the investigation.” If Trump is charged with obstruction, it will be important to see what specific evidence Smith’s team has gathered about the former President’s intent.Prosecutors also don’t have to limit their case to the crimes explicitly outlined in the search warrant. Recent reporting from the Washington Post about Trump “sometimes” showing classified documents to others raises the question of whether he could be charged under an entirely different statute, “disclosure of classified information,” which prohibits revealing certain classified material to anyone not authorized to receive it.What is Trump’s most likely defense?Since the raid, Trump has claimed that he had the power to declassify anything he wants, that he had a “standing order” to declassify documents, and that he could declassify materials simply by “thinking about it.”While there’s never been a case like this before — no former President has made such claims or been accused of such conduct — most national security lawyers say Trump’s argument is legally unpersuasive.His broad power to declassify materials ended at noon on Jan. 20, 2021, once he was no longer president. But assume, for the sake of argument, that Trump declassified information in his mind as he flew on the plane from Washington to Florida. Attorney Bradley Moss says he would have still needed to effectuate that decision in some meaningful way.”A verbal command doesn’t do it. A tweet doesn’t do it. There has to be follow-up documentation through the agencies making clear what is being declassified,” Moss told NBC News. “If not, anyone who saw it would still have to treat it as classified.” But, Moss cautioned, there’s no precedent for anything precisely like this case.Many have pointed to the fact that Smith could avoid a battle about whether the documents were declassified by charging under the law regarding “national defense” material, but Trump would still likely argue he held onto materials he believed he had the right to possess. “His best defense is he didn’t realize they were classified documents because he didn’t pack them up,” Moss added.On an obstruction charge, Trump could argue that he relied on the advice of others, believed his team was complying with demands to return the documents, or others like his valet Walt Nauta, who moved the boxes, went rogue.Where are Trump’s legal vulnerabilities?Claims of Trump’s ignorance about how the documents got to Mar-a-Lago are undercut by the fact that he held onto them, even after the government repeatedly asked for them back, says Mary McCord, the former Acting Assistant Attorney General for National Security at the DOJ and an NBC News/MSNBC contributor.”He had received a request and then a subpoena,” McCord said. “If the Archives said we need the documents back and he gave everything back right away, we wouldn’t be talking about criminal culpability.”But that’s not all. Recent news, first reported by CNN, of Trump talking on tape about a classified document he kept after leaving office and wishing that he had declassified it also hurts his case in significant ways. “It kind of locks him in,” McCord added. “It shows he actually knows he can’t show documents to people who aren’t authorized.”The recording could also be key to rebutting any defense that Trump might raise about having previously declassified everything he took after he left office.Does Trump’s motivation for keeping the documents matter?No. “Motivation is irrelevant,” Moss said. Even if Trump wanted to keep classified documents in Florida — not because he planned to give them to foreign adversary, but merely as a memento of his time as president — he could still face criminal charges.In 2017, the Justice Department charged a former defense contractor, Harold Martin, with improperly retaining national defense information. There was no evidence that Martin intended to share the materials with anyone, but the amount of information he squirreled away at his home was described as “breathtaking.” The former U.S. attorney in Maryland, Robert Hur, who prosecuted Martin, is now serving as special counsel investigating President Joe Biden’s handling of classified materials.Could Trump’s case conceivably go to trial before the 2024 election?It’s difficult to say, especially without an indictment. What’s clear is that Trump’s legal team would fight any charges and undoubtedly attempt to delay the trial.First, they would likely file multiple pre-trial motions to get the case dismissed. And if that didn’t work, his attorneys could file appeals, which would drag the process out even longer.Trump is already facing a trial in March 2024 in the New York hush money case. Soon we may find out if he’ll face another.