The writer is a contributing editor at theclaremont review of booksand author ofthe age of entitlement: america since the sixties

The announcement that us president donald trump and his wife, melania, have tested positive for coronavirus moves a new concern to the centre of american politics.

While the first priority is to wish mr trump and his family a speedy recovery, we must also reckon with the consequences of the diagnosis. should the president develop covid-19, which becomes more dangerous in older people, it will shake up the business of government. whether he does or not, the logic of an already bitter and high-stakes campaign has probably been reinforced.

The pandemic was playing havoc with the presidents political fortunes long before he got the bad news from his doctor. mr trump ran for the white house in 2016 on the claim that american institutions, public and private, had grown corrupt. it was not just that the middle class was suffering economically, while the so-called 1 per cent thrived. it was also that a class of unelected leaders were misusing power that they claimed to be exercising for the public good. experts, judges, journalists and the heads of foundations constituted acultural1 per cent. this was the swamp that he promised to drain.

Public-health experts belong to this class of people. when coronavirus struck the us, mr trump clashed with medical elites of all kinds: with the world health organization over the diseases chinese provenance; with the centers for disease control over the wisdom of deregulating controversial treatments; and with almost everybody over the effectiveness of masks.

Mr trump had some success in addressing coronavirus. he imposed early travel restrictions between the us and china. but the disease reinforced the bad feelings between him and american elites, who blamed him for its spread. a tone of schadenfreude marked newspaper death tallies.

Coronavirus reinforced another, less discussed division between the young and the old. mr trump was the candidate of those who had lost out from globalisation. that message meant less to those too young to have lost anything. in the 2016 election, he took only 37 per cent of the under-30s vote.

This years nationwide protests over the killing in may of george floyd, an african-american man from minneapolis, by a police officer became another source of division. americans had been confined to their homes for months, in many cases deprived of their livelihoods, amid stern warnings from public authorities that violations would be punished. now the streets were filled with mostly young people jostling shoulder to shoulder to protest police violence, and no consequences were being meted out.

Something broke in the us then. first, it appeared that there was one set of laws for the dowdy, big mac-chomping, trump-supporting heartland and another set for the woke, frappuccino-sipping democratic cities.

A comparison can be made with the recent covid-19 lockdowns in madrid, where residents of heavily infected working-class areas are mostly confined to their neighbourhoods, while those strolling certain caf-lined boulevards of the central city are not.

To trump supporters, locking down the country seemed to permit a takeover of its big cities by race radicals. any consensus behind across-the-board lockdowns evaporated then and has showed no signs of returning. the presidential campaign of democrat joe biden has seemed vulnerable on this issue, trying to hold mr trump responsible for covid-19-related economic slowdowns, even as mr biden calls for tightening government measures further.

It is difficult to tell whether the presidents positive coronavirus test will alter the course of the presidential race. in theory, mr trump could conceivably benefit from the news acquiring an empathy for the covid-vulnerable, while also displaying exemplary human toughness.

The evidence from the uk, however, is not encouraging. prime minister boris johnson had a case of covid-19 serious enough to merit hospitalisation, and possesses a considerably wider communicative range than mr trump. yet his pandemic-fighting policies were attacked with gusto in parliament even as he convalesced. the fierceness of the media criticism of senior adviser and brexit architect dominic cummings for allegedly violating lockdown restrictions raised eyebrows abroad.

Whatever else it may do, the virus does not provide political immunity to those who contract it. almost anything could happen. the remaining presidential debates may be postponed or cancelled, an outcome unlikely to disappoint the 69 per cent of americans who told cbs they found the opening debate in cleveland annoying.

Twitter being a medium one can deploy from isolation and even the sickbed, we may hearmorefrom the president in the short term. or we may now begin to hear his message from less abrasive and less charismatic surrogates. either way, we are about to get some indication whether trumpism is a sturdy ideology that can stand on its own, or a personalistic movement that requires the presidents undivided attention.