For the entirety of Ronald Reagan’s first term, despite overwhelming evidence that Aids was a public health crisis, he brushed off the disease’s severity, saying “it would go away”. By 1987, Aids had killed more than 29,000 Americans. In that same year, Don Francis, an official at the Centers for Disease Control and Prevention, testified before Congress that Reagan’s administration caused “untold hardship, misery and expense to the American public” by obstructing, resisting and interfering with policies and programmes designed to prevent the Aids epidemic in the US.

Certain factors at play in the Aids epidemic are not at play in our current pandemic: most obviously, Covid-19 is not associated with the gay community. Nonetheless, there are echoes of Reagan’s response to the Aids epidemic. Last month, days after California had declared a state of emergency and Seattle schools had begun to close, Donald Trump asserted that Covid-19 would simply “go away”. Shortly before that, he said that it would “disappear … like a miracle”. Trump was joined in his parade of denial by other far-right populist leaders, especially Brazil’s president, Jair Bolsonaro. In March, he described Covid-19 as a “little flu” that does not warrant “hysteria”, and claimed that Brazil would be protected from the virus by its climate and youthful population.

We need leaders who allow public health experts, rather than their political self-interest, to guide policy

What motivates men like Trump and Bolsonaro to deny, falsify and dismiss evidence about public health crises?

One salient feature stands out as common among these men: toxic masculinity. The concept has become popular, with Google searches for the term skyrocketing in January 2019 when the shaving company Gillette released a series of advertisements that challenged traditional expressions of masculinity, such as bullying, suppressing emotions and sexual harassment. Those advertisements set off a public debate about whether toxic masculinity is a helpful concept. Some took to Twitter and other media to complain that “masculinity isn’t a sickness”, while others, like the American Psychological Association, maintained that these traditional forms of masculinity harm not only men, but also those around them.

The current pandemic throws into stark relief how useful the concept of toxic masculinity can be. Dr Roger Kirby, a men’s health expert, observes that toxic forms of masculinity, which lead to “dominant, aggressive, [and] risk-taking” behaviour, cause men to see illness or other health problems as effeminate and weak, leading them to choose risk and discomfort over the “emasculation” of seeking medical treatment. As a result, men who pursue these forms of masculinity display “the strongest predictors of individual risk behaviour over the life course”.

Trump and Bolsonaro are clear examples of men who cling to toxic forms of masculinity. They lash out at anything that threatens their dominance, and rely on misogyny and violence to bolster their egos. They denigrate women and femininity in order to reinforce their fragile sense of their manhood, referring to women as “slut[s]”, “dog[s]” and “piece[s] of ass”. Trump has boasted about his penis size and testosterone levels, and Bolsonaro said that he would rather have a dead son than a gay one. Both frequently encourage or excuse violence, and rage at those who disagree or make fun of them. They are two peas in a pod. And in our current crisis, their toxic masculinity is a deathly threat. It plays out in the most literal sense: it risks physical harm to others and themselves.

True to this prediction, Trump recently made headlines for initially refusing to take a test for Covid-19, obey physical distancing guidelines or wear a face mask, undermining his own health experts’ recommendations. Bolsonaro, following suit, declared that his manly history “as an athlete” would protect him from the virus. And while it is tempting to laugh at the absurdity of Bolsonaro’s claim, the sobering reality is that Trump and Bolsonaro’s behaviour has an ever-rising body count.

Now that this lie is no longer sustainable, Trump and Bolsonaro have pivoted. Both currently attempt to cast themselves as hyper-masculine “wartime” heroes, committed to protecting their countries from a “hidden enemy”. One form of muscular egoism replaces another. These militaristic self-portraits make clear that Trump and Bolsonaro are focused on stoking partisan divides and winning re-election, and not on doing what is needed to save lives.

We do not need patriotism and weapons; we need globally connected medical research, social safety nets and healthcare. We need leaders who allow public health experts, rather than their political self-interest, to guide policy. We find ourselves in a time that calls for traditionally “feminine” traits, such as empathy, solidarity and compassion. The men in charge have chosen to prioritise their precarious sense of manhood, rejecting scientific evidence, deploying rhetoric of violence, war and division, and placing us all in harm’s way.

• Robin Dembroff is assistant professor of philosophy at Yale University