MOST Americans surveyed, Democrats as well as Republicans, believe that Joe Biden is unfit to be President. There is no compelling evidence for that: plenty of people disagree with President Biden’s policies, but few doubt his effectiveness in office during the past four years.

And it is hard to see what better evidence there could be of his fitness for the job than past performance. Even if, as some say, his team of advisers have been running the country since he sank into dotage, they have done a good job, and there is every reason to believe that a Biden administration would, one way or the other, do just as well during the next four years.

But even if President Biden, on his own or through the efforts of his team, is qualified to lead the country, he is not qualified to campaign — and so he should drop out of the presidential race. He cannot win. Americans have always prided themselves on “voting for the man, not the party”, and Biden is not the man.

Currently, 49 per cent of Americans declare themselves “independents”, unaffiliated with any political party. They vote for the candidate who “looks presidential” — for his oratory, and, above all, for his displays of strength; think Chairman Mao’s swim in the Yangtse River, President Putin’s shirtless horseback ride, or the independent presidential candidate Robert Kennedy Jr’s shirtless push-ups on social media. And it is the man — always a man, and in almost every case, the taller man — who brings his party into office, not vice versa.

MR BIDEN, shuffling and stuttering, cannot win. But the Democratic Party cannot force him out of the race. In the United States, it is voters, through a system of state primaries and caucuses beginning months before the general election, who choose the man to lead their party and stand as its candidate for the presidency.

Once chosen, delegates to party conventions, where candidates are formally nominated, are pledged to nominate the chosen candidate, and cannot withdraw their support. Even if Mr Biden, who has locked in the nomination, were to withdraw voluntarily, it would be virtually impossible to avoid replacing him with Vice-President Kamala Harris, whom many Americans regard as odious.

If the US operated according to a parliamentary system, and Mr Biden were the MP for Delaware, chosen by Democratic MPs to lead their party and serve as head of government, there is no doubt that he would be replaced. It is certain, also, that his successor would replace Ms Harris as well.

After Mr Biden’s disastrous performance at the first presidential debate, no damage control is possible, because the damage to him was done much earlier, when his opponents began harping on about his age and liberal pundits amplified the message in hopes of persuading him to withdraw from the race. Polls after the debate showed barely a dip in Mr Biden’s consistently dismal approval rating, because, by the time he shuffled on to the stage, most Americans had long been convinced that he was deep into cognitive decline and unfit for office.

Mr Biden now trails Donald Trump by six percentage points, his disadvantage in the polls is growing, and he is almost certain to lose the forthcoming election. If he withdraws, and the Democratic Party replaces him and Ms Harris with a pair of young, telegenic candidates, it is likely that the Democrats will win the presidency and additional congressional seats.

IF HE stays in the race, and Mr Trump wins, then, instead of claiming his legacy as an excellent public servant and effective President, he will be vilified as a spoiler several orders of magnitude greater than Ralph Nader, the Green Party candidate who threw the 2000 presidential election to George W. Bush.

Mr Bush was a mediocre President, but his victory did not upset the world order. If Mr Trump wins, the consequences will be global: he will cede Ukraine to the Russians, betray America’s democratic allies, and affiliate with strongmen in authoritarian regimes abroad. Domestically, he will dismantle our already minimal social safety net and eliminate regulations that ameliorate ongoing discrimination against women and minorities. And, in the American political system, once Mr Trump is elected to the imperial presidency, it will be impossible to stop him.

The US was an early adopter of the republican system of representative democracy. Like its early adoption of computer technology, this locked the US into an antiquated system that does not serve current interests. With the ubiquity of mass media, the American presidential system, in which a single individual is head of state as well as head of government, virtually guarantees that presidential races will be decided on optics.

It does not matter whether President Biden is an effective head of government or is competent to lead the country: in this system, he cannot win.

Dr Harriet Baber is Professor of Philosophy at the University of San Diego, California, in the United States.