Which criminal case may be hardest for Trump to win?

Three indictments, 78 charges, three trials. What might Donald Trump's defence be in court and which of the three cases will be hardest for him to win?

The former president stands accused of a litany of crimes. Conspiring to overturn the 2020 presidential election. Undermining Americans' right to vote.

Hoarding classified documents at two of his properties. Using fraudulent means to pay off an adult film actress in the heat of the 2016 race.

He faces nearly 80 counts in three states and possibly more if, as expected, he is indicted for election interference in Georgia.

We have seen the prosecution's case as laid out in the indictments but what do we know of how Mr Trump will defend himself at the trials next year?

The most interesting dynamic is found in the Florida classified documents case, legal experts tell the BBC.

"While it's probably the strongest case legally - it is absolutely airtight - the jury pool might be favourable enough that Donald Trump will be able to essentially get a juror or a handful of jurors to nullify and get him out of it," said Anthony Michael Kries, a professor of election and employment law at Georgia State University.

The Department of Justice has accused Mr Trump of illegally taking classified White House materials after he left office, storing them improperly at his Mar-a-Lago estate and then obstructing the government's repeated attempts to retrieve the documents.

US law requires departing presidents to hand over such materials to the National Archives. There is a tried and tested law governing the possession of classified material and plenty examples of case law to draw on. Other ex-officeholders, such as former Vice-President Mike Pence, have returned such documents as soon as they found them.

The indictment lays out reams of evidence against Mr Trump, including photos of boxes stored haphazardly at his Florida home. Prosecutors even obtained audio of Mr Trump talking about a classified document in front of people without proper clearance, and admitting he could not declassify the material now that he had left office.

Mr Trump has inaccurately claimed in public that he could have declassified the documents. He pleaded not guilty at his arraignment in Miami in June and has called the prosecution politically motivated.

But he could find favour in the state's jury pool. Mr Trump is loved and loathed equally in southern Florida and legal experts based there say choosing an impartial jury could prove challenging.

"The added element is people with agendas," Rob Mendell, a Florida trial attorney, told the BBC in June.

The first case Mr Trump faced this year may prove the most straightforward for him to win.

In March, New York prosecutors issued 34 felony charges of falsifying business records. These relate to a $130,000 hush money payment Mr Trump's lawyer made to an adult film star in the final weeks of the 2016 election campaign.

The cash was to stop her talking about an alleged affair, a relationship denied by the former president. Manhattan district attorney Alvin Bragg alleges that Mr Trump funnelled the payment through his lawyer, Michael Cohen, and fraudulently recorded the payments as legal expenses.

Ordinarily, falsifying business records would only amount to a misdemeanour but Mr Bragg has made this a felony which requires him to prove the false accounts were covering up another crime.

It is unclear what that second crime could be.

Federal investigators chose not to bring a prosecution in this case and some legal experts believe it will be a tough one to prove because of Mr Bragg's novel approach.

The case was "probably the weakest in terms of legal theory and I think it's come under considerable criticism by even liberal legal experts," said Mr Kreis.

Last week, the Justice Department charged Mr Trump on four counts related to election fraud. It's an unprecedented case, involving a president allegedly trying to use the levers of government to cling on to power.

He is accused of pressuring election officials and the vice-president to change the outcome of the 2020 election, which he lost to Joe Biden. He also stands accused of widely spreading disinformation that the election was stolen, which ultimately led to the US Capitol riot.

Some legal experts think the litany of evidence, the unsympathetic jurisdiction of Washington DC, and the way Special Counsel Jack Smith constructed the case all mean it's an uphill battle for Mr Trump.

"The election violation in DC - I think that is a legal slam dunk," said Mr Kreis. "I think that might be the hardest [for Trump] to beat."

One crucial factor Mr Trump can fight against is the issue of intent, whether or not he actually planned to commit these crimes. Prosecutors will have to show that Mr Trump knowingly made false claims in the service of committing crimes.

"The person has to know that it's false, and then purposely, intentionally make the statement, for the purpose of influencing government activity," said Morgan Cloud, a professor at Emory University Law School.

That is the key, adds Mr Kreis. "Did Donald Trump honestly believe and honestly come by his understanding that the election was fraudulent and that he had actually won?"

Mr Smith went to great pains in the indictment to show multiple moments where top aides and allies warned Mr Trump that the election interference claims were bogus, yet he proceeded anyway.

His lawyer John Lauro said the former president believed "in his heart of hearts" that he won the election and the prosecution will not be able to prove otherwise. His client was being attacked for exercising his First Amendment right to free speech, he added, and his requests to election officials were just "aspirational".

There is a strong chance, however, that Mr Trump cannot rely on a free speech argument. Some of what he said might be protected by the First Amendment, said Aziz Huq of the University of Chicago Law School. But, he added, "speech that is used to facilitate the crime is almost never covered".

Mr Smith made this point in the indictment, that while Mr Trump could freely say what he liked about the election outcome, he could not use that belief to try to overturn the result.

But not everyone believes the case will result in a conviction.

Sarah Isgur, legal commentator at conservative website The Despatch, told the Economist the statutes under which these counts were brought require proof of intent. This means the fact that people were telling him his claims were untrue is not enough, she said.

Mr Trump can also point to lawyers like John Eastman and others who were telling him his claims were correct, she added.

Regardless of how both sides argue the case, they must convince a jury. And it is this variable that legal experts say is most difficult to predict.

Four different jurisdictions at play - Washington DC, Florida, Manhattan and potentially Georgia - will result in four very different jury dynamics.

The threshold for a conviction is beyond reasonable doubt and decisions must be unanimous, two factors in Mr Trump's favour.

"That's certainly going to make Trump's case easier," says Mr Kreis. "He doesn't need to convince 12 people… they only need one person."

The other big variable is Mr Trump himself.

In theory he could delay any convictions by appeal, win the presidency, and press the Department of Justice to drop its investigations.

Or even, as he has reportedly mused in the past, pardon himself.