The peril grows from Trump's Georgia prosecution, as his co-defendants fall like dominoes

Fani T Willis, the district attorney for Fulton County, Georgia, has been making significant progress in her sweeping racketeering case against former US president Donald Trump and 19 co-defendants. She has rapidly secured plea deals and binding pledges of co-operation from key defendants, including former Trump attorneys Kenneth Chesebro, Jenna Ellis and Sidney Powell, as well as Atlanta bail bondsman Scott Hall. More central defendants such as campaign attorney Rudy Giuliani and Mr Trump must be squirming.

Ms Willis's racketeering case is structured like a pyramid with marginal figures such as Mr Hall at the bottom and Mr Trump at the apex. Plea deals with less prominent defendants secure testimony against more senior figures. The idea is to begin at the base and work up to the very top of the alleged racketeering structure. That Ms Willis has already "flipped" some significant defendants suggests she knows what she's doing.

Fragments of their confidential depositions have been leaked to the media. Ms Ellis, for example, testified that Mr Trump's then-deputy chief of staff Dan Scavino – a key aide who long managed his social media presence – responded to her observation that they were quickly running out of legal options to block Joe Biden's victory from being formally confirmed by excitedly insisting, “Well, we don’t care, and we’re not going to leave.” She said she understood that to mean that Mr Trump and his inner circle were determined to ignore the election results and the law and simply stay in power even if they lost cases and ran out of legal arguments.

This testimony may prove to be more appalling than an evidentiary bombshell. It could well be excluded from the trial on the reasonable grounds that it constitutes hearsay, and, if it is allowed, Mr Trump's attorneys will undoubtedly argue that whatever Ms Ellis thought Mr Scavino was trying to say, the only relevant fact is that Mr Trump did, in fact, leave the White House, albeit without conceding defeat. However, it indicates the kind of testimony that can pile up against more significant defendants when less central figures decide to protect themselves by revealing the truth under oath.

Perhaps more significantly, Mr Chesebro testified that he personally briefed Mr Trump about a legal memo outlining a plan for Republican-dominated legislatures in states won by Mr Biden to organise "fake" electors who would seek to fraudulently cast votes for Mr Trump in the electoral college (which technically elects the US president), thereby nullifying and reversing the outcome of the election and unlawfully keeping him in power. This may be one of the strongest pieces of evidence yet that Mr Trump was well aware of the unlawful "fake electors" scheme that his campaign and supporters were pursuing to try to negate the election results.

In Mr Trump’s favour, however, both Ms Ellis and Ms Powell say they believe he had somehow convinced himself that he had, in fact, won the election and was the target of a gigantic election fraud conspiracy. His state of mind and beliefs could be significant in determining his guilt on the charges that centre on intent to break the law, such as those arising from his notorious telephone call to Georgia Secretary of State Brad Raffensperger. Mr Trump demanded that he "find" 11,780 extra votes for him in the state, exactly the number he needed to reverse Mr Biden's Georgia victory. Mr Trump even appeared to threaten Mr Raffensperger with unspecified criminal exposure, seemingly suggesting that he might face prosecution if he failed to manufacture precisely this number of non-existent votes.

This case is likely to hinge on whether it is a violation of Georgia criminal law – and by implication, more broadly, law throughout the US – for politicians and officials to conspire to overthrow a legitimate election result, thereby undoing the US constitutional system, under the cover of merely giving and receiving legitimate legal advice. The defence in this case for both Mr Trump and these attorneys may ultimately come down to the question of whether it is criminal to use legal manoeuvring – in contrast to the more obviously unlawful violent assault on Congress on January 6 that sought to block the formal confirmation of Mr Biden's victory in the popular vote and in the electoral college – to attack the most fundamental elements of the US constitutional system: free and fair elections and the peaceful transfer of power.

As Charles Burnham, an attorney for law professor John Eastman, the main author of the "fake electors" scheme, argued: “Professor Eastman has no problem with Greg Jacob, Ken Chesebro or anyone else disagreeing with his arguments. The whole point of this case is that legal disagreements on unsettled questions of constitutional law should not be criminalised.”

To put it in layman's terms, that means this wasn't an attempted coup at all, it was just a question of conflicting legitimate legal opinions. And, therefore, it would be absurd and outrageous to criminalise the giving and receiving of legal advice. These are indeed "unsettled questions of constitutional law" largely because no previous president has had the temerity of attempting a legal coup.

Both Ms Powell and Ms Ellis acknowledged that Mr Trump was relying on their highly dubious advice because, unlike virtually all government and Trump campaign attorneys who unanimously insisted that he needed to accept his defeat, they were telling him what he wanted to hear: that he could somehow remain in power and nullify his defeat through brazen legal manoeuvres.

The argument that it's all just a matter of conflicting legal opinions is clever and seemingly plausible, but if the US Constitution cannot protect itself from subversion through conspiracies of legal chicanery, just as much as from threats posed by violent uprisings, it is a fatally weak and fundamentally incoherent document.

Ms Willis says the Georgia trial will not conclude until at least early in 2025, well after the November election. But what's most significant about her case, as opposed to analogous federal prosecutions being led by Jack Smith, is that neither Mr Trump nor any Republican president, if they win, could interfere with this state trial or undo any sentence.

If Ms Willis can continue to get Mr Trump's co-defendants to fall like dominoes, each knocking down the next, their testimony – combined with existing damning evidence such as the recording of the Raffensperger phone call – she may have created the one serious criminal prosecution which affords Mr Trump no strong defence and no way out.