I'll explain why.
But to understand, one needs to understand the role that televised debates still play in the US election.
On a typical night, Fox News, which is the most watched news channel among cable TV channels in the United States, has about 4-5 million viewers on average.
In 2016, nearly 85 million Americans watched the first debate between Donald Trump and Hillary Clinton, and there may be even more this year.
About 10 percent of voters have said after the last election that they decided who they wanted to vote for in connection with or shortly after the debates.
That sounds like a small number - but remember that no candidate has won the people's vote in the United States by more than ten percentage points since Ronald Reagan won by 18 percentage points against Walter Mondale in 1984.
Trump is considered stronger in TV debates
So there are important voters to fight for and of course the debate means a lot to President Trump.
He has a heavy public opinion uphill to stand up for if he is to be able to win the election, and precisely in the debates something must now happen for Trump.
This is especially so since the president is considered to be significantly stronger in TV debate contexts than Joe Biden, who delivered some pale contributions during the primary election debates last year, not least against his vice-presidential candidate Kamala Harris.
Expect a Donald Trump who criticizes Biden for his son's business in Ukraine, for the violence in connection with demonstrations around the United States and for the information about suspected election fraud that has come from several places in the United States in recent days.
But unlike 2016 when everyone's eyes were on Trump, the situation is now the opposite.
Biden must prove himself worthy of leadership
It is Joe Biden who must prove that he deserves the leadership in public opinion he sees right now.
Many insecure Americans will not have been able to escape all the deliberately spread rumors that Joe Biden was too old, fragile or even senile to become president.
It does not matter how many times the Biden campaign denies such accusations, many viewers will carefully examine how Biden behaves on stage.
This is not necessarily a bad thing for Biden.
Historically, before the debates, both parties have tried to tone down the expectations of their own candidate, so that he can "surprise everyone" during the debate and do well.
That opportunity now exists for Joe Biden, who in principle only needs to do decently to be considered to have done well.
Yet.
It is Joe Biden who has everything to lose in the first debate.
It is Joe Biden who in the weighted opinion polls leads by about 7 percentage points, with clear leads also in several important insecure states, such as Pennsylvania.
And it is Joe Biden who must prove that he - in his own words - knows how to handle the "bully" Trump.
Keep an eye on Biden
Expect him to criticize the president's handling of the corona crisis, Trump's modest federal income tax over the years, and the swift nomination of a new judge to the Supreme Court.
But keep a close eye on Joe Biden.
A few moments where he looks "old and fragile" will be inflated to large proportions.
Also pale debate efforts like those this spring.
Then Biden's leadership can quickly begin to be eaten up by those ten percent of voters who have listened particularly carefully to the debate.