How does one debate Donald Trump?
The team behind the Democratic challenger Joe Biden will have spent the past few weeks devising a plan to answer this - ahead of this afternoon's first presidential debate.
What makes it so difficult is how unconventional the president is, especially in his treatment of the truth.
Four years ago, Hillary Clinton's approach to challenging Trump during their debate was to promote a website that fact-checked his comments in real time.
Fact-checking is a job for the candidates, but more importantly, Biden's team will be telling him to stay on message, and to keep Trump on the defensive.
The winner will ultimately be he who delivers the biggest moments that will be replayed online and on television for days, and years, to come.
Four years ago, Trump arguably had more of these - such as his response to Clinton wondering what would happen if he were to bear responsibility for US law: "You'd be in jail," he replied.
The official talking points for this afternoon's debate have been chosen, signalling the direction that moderator - Fox News' Chris Wallace - will take.
They are the candidates' personal records, the Supreme Court, Covid-19, the economy, race and violence in US cities, and the integrity of the election.
Yet both Biden and Trump will have their own agendas, and talking points they want to hit, and hit hard:
The biggest story of this week, and of the entire election race, is the revelation by The New York Times that Trump has avoided paying virtually any income tax over the past two decades.
Throughout his political career, he has billed himself as a successful businessman capable of engineering an American resurgence.
Instead, the article depicts a man who religiously practices tax avoidance to protect his worth.
The Trump administration has already hit back, claiming the Times' reporting is inaccurate, yet yesterday the president tweeted that he is as entitled to tax credits as any other American.
Biden is certain to attack Trump along these lines, perhaps even making jokes about the hundreds of millions of dollars in loans he reportedly owes, or the tens of thousands he has spent on hair styling.
Whether this resonates with moderate voters remains to be seen.
Biden's state of mind
The president has frequently attacked Biden for his mental state, even suggesting, without evidence, that he has dementia, dubbing him "Sleepy Joe."
Trump has even called for his rival to be drug-tested before the debate, again suggesting that he relies on some sort of medication to be able to speak coherently.
Biden needs to put this to bed.
He has spoken well at key times in the past few weeks, specifically for 25 minutes at the Democratic National Convention, but in the age of social media and viral videos, he's still managed to go viral for stumbling over his words when he's gone off-script.
If the same thing happens this afternoon, Trump will smell blood in the water and attack.
Biden is only two-and-a-half years older than the president, yet the cut-through of this perception could be very damaging.
More than 200,000 Americans have so far died due to the pandemic, vastly more than any other country, while more than seven million have been infected.
The president has repeatedly claimed he's done an A+ job responding to the coronavirus, yet the facts paint a different picture.
Right now, more than 20 states are seeing an increase in new infections, and the Trump administration's response over the past few months has been to defer responsibility to the states.
Trump will likely point to his promise that a safe vaccine will be rolled out across the country in a matter of weeks - a claim that's yet to be backed up by science.
Biden will need to clearly explain how he would have done a better job - something he's yet to do - and tell the American public that things didn't need to get this bad.
Trump has also for years promised his own health care plan, and is yet to deliver.
Law and Order
This election will likely be determined by if, and how minority communities vote - as it has done throughout American history.
Trump has several times claimed he's done more for African Americans than any leader since Abraham Lincoln - a quite incredible claim.
Yet his term has seen some of the most significant racial unrest ever seen - massive protest movements like Black Lives Matter - which he's put down as simply the actions of rioters and looters.
He has billed himself as the ultimate "law and order" president, striking fear into the hearts of voters that if he loses November's vote, things will get worse.
Biden will try to depict his rival as an antagonist who has only stoked the violence and fanned the flames of unrest.
Trump is yet to concede that America has a problem with racial inequality and profiling - Biden will need to show he is the person to solve such issues.
The death of the liberal icon Ruth Bader Ginsburg has sparked a fierce political battle that Republicans seem destined to win.
Trump has named his nominee to replace her as the latest Supreme Court Justice - Amy Coney Barrett - and a successful vote in the Senate should come at the end of October.
Democrats have accused the party of hypocrisy, saying four years ago Republicans argued such a vote must wait until after an election year.
Biden has already said Coney Barrett could represent an end to the Affordable Care Act, known as Obamacare, and promised that if he is elected, he would nominate the first African American woman to the Supreme Court.
Meanwhile, when it's suited him, Trump has painted himself as the arbiter of conservative values - of Christian values - appealing to the Republican Party's base.
When protesters were violently swept off the streets of the capital, he brandished a Bible outside a church, holding it aloft for cameras.
It's entirely possible that the faith - and the devoutness of both candidates - is also debated.