Now that Republican Ron DeSantis has officially declared his presidential candidacy, it has once again become clear which opponent could really scare Joe Biden: a smart, educated candidate like DeSantis, who credibly promises to complete Donald Trump's work – and whom Trump therefore supports with all his might.

But Biden has little to fear. DeSantis is running in the primaries not with Trump's blessing, but against Trump. If he promises to really build a wall on the border with Mexico, because that has not happened; when he talks at length about the danger of a growing China, without at the same time raving about the communist ruler Xi Jinping with reverence; if he does all this on Trump's former favorite platform Twitter, then he does not look like the executor of Trump's vision, but like a troll to many Republicans in the country.

Not to mention the slogan that Republicans must overcome the "culture of losing," a pointed reference to Trump's whining about "witch hunts" and his "stolen election victory." In doing so, DeSantis does not conquer the hearts of true Trumpists.

It can also be too much brain

Regardless of Trump, Florida's governor has yet to prove that he has what it takes to survive on the national stage. The history of American primaries is rich in supposedly strong candidates who only realized late what it means when every half-sentence is weighed on the gold scale.

But if DeSantis wins the Republican primaries against Trump and all other candidates, then his ideological positioning as an arch-conservative fighter against "wokeness" is unlikely to be the biggest hurdle in the fight against Biden. First, Trump has pushed boundaries, and in social policy, Biden's Democrats seem no less extreme to many Americans. Many actually long for a "Trump with brains," as DeSantis is often called. Second, the governor's work in Florida shows that he does not shy away from tactically adjusting his positions. Sharply to the right in the primaries, then back to the center in the main election campaign – that's what American voters are used to.

The bigger problem would be mobilization. Trumpism's calculations work when millions and millions of politically disenchanted, uneducated Americans go to the polls, while many Democrats stay away from the polls due to a lack of enthusiasm for their candidate (or fear of his opponent). So far, however, DeSantis does not speak the language of this clientele, which Trump has opened up to the Republicans – it can also be too much brain.

Donald Trump could compensate for this weakness by campaigning passionately for DeSantis. Instead, he will use the next few months to convince his base that DeSantis is playing the wrong game. Joe Biden will enjoy the spectacle.