If what happened in the UK last December is any indication, then all Trump needs to win is One Big Issue he can take a clear-cut stand on, but the Democrats can’t.
It was the Brexit issue that cost Labour the last UK election. Their programme was popular, sensible, fully-costed and promised a return to a decent quality of life for an awful lot of people. But, despite massive evidence that core Labour voters where overwhelmingly pro Leave, Labour could not bring themselves to commit fully to Brexit. The Conservatives fought the election on that one issue — Brexit at all costs - and they won a landslide victory.
If the coronavirus does become a global pandemic, all Trump needs to do is to say “We will keep coronavirus out of America by keeping all foreigners out of America!”, and he will win again. If that doesn’t happen, look for a 9/11 level event this summer that Trump can take a hard stance on.
If Roosevelt could turn a blind eye to Japanese plans to attack Pearl Harbor in order to have an excuse for extending Americas’ sphere of influence in the Pacific, then Trump would have no issues about arranging a ‘terrorist’ attack on US soil in order to stay in the White House.