It was important to US president Donald Trump to beat Covid-19. Not to recover from it, or to be successfully treated for it, but to beat it, as you would a wrestling enemy with the back of a chair. Already he has begun reframing his hospital discharge as a sign of strength. On Monday, campaign adviser Mercedes Schlapp told Fox News: “We’re going to defeat this virus. We’re not going to surrender to it like Joe Biden would surrender,” deliberately leaving open the interpretation that the relevant “surrender” was getting sick and dying. The president retweeted columnist Miranda Devine’s characterisation of him as an “invincible hero, who not only survived every dirty trick the Democrats threw at him, but the Chinese virus as well”.It is the latest instalment in a long history of the conflation between physical fitness and fitness for office, as though facts about a person’s character can be deduced from whether they get sick.Rightwing, authority-hungry leaders often make this move. From the state of their bodies we are supposed to deduce things about the state of their person. Vladimir Putin rides horses shirtless; shoots tigers; hugs bears. Jair Bolsonaro removed his mask after his Covid-19 diagnosis to show reporters how little it affected him. “Just look at my face, I’m fine”, he said.When these are the characters who voice a connection between physical wellness and moral character, the falsity of that connection is obvious. It is cartoonish, even – Trump himself is so obviously unfit (apparently owing to a belief that humans are born with finite heartbeats and to exercise is to waste them) that it’s almost impossible to take the position seriously.But the presumed link between physical health and strength and worthiness is far more politically widespread. In March a staffer for Democratic candidate Elizabeth Warren tweeted a photograph of her jogging jauntily up a set of stairs, hair springing with her gait, while fellow candidate Bernie Sanders trailed behind her on an escalator, paunched and balding. “This hits me so hard,” said the staffer, assuming an obvious connection between physical mobility and leadership.The character endorsements for “fighters” who make it through disease are common; Gabrielle Giffords’ recovery from a cranial gunshot wound was used to show her strength of character, and Barack Obama –in his own right a good athlete – took many photographed opportunities to play basketball in shirtsleeves. Former Australian prime minister Tony Abbott was possessed of genuine physical strength, which the public was seldom able to forget, as his rivals needed help to do a pull-up or failed to sink a basket.The assumption in all cases is that the visual impression of a person’s body is a reasonable guide to their character, or that since certain traits express themselves physically, the physical lack of those things shows they are lacking in the person’s character. This is just a bad and backwards deduction; intellectually energetic people are often physically spry but not all un-spry people lack intellectual energy. But this does not stop candidates leveraging physical wellness as a sign of some deeper strength.Now, of course, a candidate for political office has to be well enough to do the job. There are reasonable criticisms of an ageing political class and of specific individuals who stay in their jobs past the point where they can do them well. When your job involves working on other people’s behalf, you have to be able to do it better than the next best candidate, and there are some forms of physical wellness that bear on whether that’s true.But the broader connection between vitality, power and physical health is damagingly false whether it comes out of Trump’s mouth or the Warren campaign’s. It should be seen with special suspicion by those committed to accessible healthcare, a policy built on the idea that whether you are sick is not a function of what you deserve and that usual interventions of character will not save us.If – as most of us do – we believe that physical illness is not a sign of decrepit character or weakness, then we have to be careful about the photonegative thought that physical wellness is a sign of burnished character or strength. It is not only Trump and his fellow rightwing personality-leaders who seek to leverage that thought. Political positioning everywhere leverages the idea of physical health as strength, which in turn licenses the associated thought that physical illness is weakness. Whichever side of politics it appears on, that thought hurts millions of people. As any sufferer of chronic illness will tell you, the presumed connection between character and body runs deep in society, in the glances of strangers, the minds of loved ones.The president’s bizarre machismo around the virus is just the latest and most visible expression of that thought. Perhaps seeing it in such an extreme form can help us identify its more pedestrian, creeping, insidiously ordinary forms. We would do well to regard them, too, with the same sense of absurdity.• Eleanor Gordon-Smith is a writer and ethicist currently at Princeton University More