Mr Trump was initially charged in an indictment unsealed on 9 June with 37 criminal counts, including violations of the Espionage Act, conspiracy to obstruct justice and making false statements to investigators in relation to a stash of top secret papers that had to be recovered from his Mar-a-Lago estate in Palm Beach in the aftermath of his presidency after repeated requests for their safe return by the National Archives and Records Administration (Nara) in 2021 went unanswered.
On 27 July, prosecutors filed a superseding indictment in the case, accusing Mr Trump of an additional count of illegally retaining national defence information.
The former president allegedly boasted in 2021 that he held onto a secret military document about Iran, saying in a conversation that was allegedly recorded that he knew the material was “still secret.”
The new indictment also accuses Mr Trump and a previously unnamed aide, Carlos De Oliveira, of attempting to “delete security camera footage at the Mar-a-Lago Club to prevent the footage from being provided to a federal grand jury.”
According to the Presidential Records Act, White House documents are considered the property of the US government and must be preserved in the interests of national security.
The Republican did eventually hand over 15 boxes of files to Nara in January 2022 containing more than 700 pages of records. In total, the boxes were found to contain 184 documents with classified markings, including 67 marked confidential, 92 secret and 25 top secret.
Not satisfied that they had the complete set, Nara officials referred the matter to the Justice Department, which issued a grand jury subpoena the following May demanding that Mr Trump return all other government records still in his possession.
His attorneys later turned over another 38 pages marked as classified and attested that all such records had now been handed back, a claim that later proved to be false.
The FBI then searched Mar-a-Lago on 8 August after obtaining a warrant from a judge and seized another 13,000 records from his presidency, about 100 of which were classified and several more top secret.
That meant that, in all, approximately 300 classified documents, some of which were considered to be at the very highest level of sensitivity, have now been recovered from Mr Trump.
US attorney general Merrick Garland subsequently appointed special counsel Jack Smith to preside over all criminal matters relating to Mr Trump, including the classified documents investigation, on 22 November.
After the unsealing of the indictment, Mr Trump was arrested and arraigned in federal court in Miami on 13 June, where he entered a not guilty plea before resuming his attacks on both Joe Biden and Mr Smith from the podium and on social media.
The most serious charges he now faces over his failure to cooperate are 32 counts brought under the Espionage Act, which criminalises the unauthorised possession of national defence information and is punishable by up to 10 years in prison.
The First World War-era law predates the classification of government documents but makes it a crime to willfully retain sensitive information that could be of use to foreign adversaries.
The existence of an audio recording of Mr Trump speaking to associates at his Bedminister golf club in New Jersey in July 2021 – obtained and broadcast by CNN last month and already in the possession of Mr Smith – that appears to reveal him showing off a “big pile of papers” including a top secret Pentagon plan of attack against Iran threatens to complicate his defence considerably.
Mr Trump is also charged with several counts of obstruction of justice, which criminalises any “intent to impede, obstruct, or influence” an investigation, and with making false statements to investigators.
To prove those allegations, prosecutors will need to show that the former president’s actions were intentional and that his goal was to hinder the probe, regardless of whether those efforts were successful.
For his part, Mr Trump has routinely insisted that the investigation is just another politically-motivated “witch hunt” against him.
He is expected to argue that he is being selectively prosecuted by a Justice Department operating at the whim of his political enemies, stressing the fact that both Mr Biden and his own former vice-president Mike Pence have not been charged after it was discovered that they too had retained classified records at their homes.
Mr Trump’s lawyers insist the whole affair is part of a much larger pattern of prosecutorial misconduct, although they have provided few details to substantiate this beyond claiming that investigators violated a legal doctrine that permits people to keep communications with their lawyers private.
Legal experts say claims of selective prosecution are usually doomed to fail because defendants must prove that they were intentionally singled out for arbitrary reasons and that prosecutors declined to bring charges against other people in similar circumstances.
Unlike Mr Trump, however, Mr Biden and Mr Pence immediately returned their records and cooperated with official efforts to hunt down further documents. The Justice Department is still investigating the Biden matter but dropped a separate probe into Mr Pence on 1 June.
Mr Trump has also claimed that he personally declassified the documents before removing them from the White House, which was within his powers to do as commander-in-chief but is an action ordinarily backed up by written documentation communicated through the established channels.
He is yet to provide any evidence of that sort to prove he actually did declassify the records.
As for obstruction, the former president could argue that he was simply acting on what he believed was sound legal advice from his lawyers and is therefore is not guilty of criminal intent.
He might also seek to shift blame to subordinates or accuse them of going rogue.
Additional reporting by agencies
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies