So let’s think about this.

Scenario A: the number of US coronavirus cases and deaths peaks in mid-May and then begins to slowly descend. By July they’re low enough that the Democrats decide to hold their nominating convention in Milwaukee with a small number of people physically present and practicing social distancing, and the state delegations represented via Skype and Zoom. Biden is nominated, and he selects Amy Klobuchar as his running mate. The party, including Bernie Sanders, rallies around them.

Meanwhile, Trump takes personal credit for “defeating the hidden enemy” and for the resulting recovery of the stock market. The travel industry is still reeling, but planes are beginning to fill up again. New Yorkers crawl out of their warrens and squint at the sun. Quarantining and social distancing recommendations are lifted in a patchwork of states and counties around the country, and schools, restaurants and stores in those locations begin to re-open with limited hours and occupancies.

By November, conditions in the bulk of the country have begun to resemble normalcy. GDP is still a fraction of previous years, but Trump crows that his actions saved the economy and the country. Biden relentlessly hammers on the lack of preparedness and leadership that exacerbated the crisis in the first place and extended its duration. The issue of how the pandemic was managed eclipses all other measures of Trump’s presidency; the impeachment, his attacks on the media, the incredibly high rate of turnover in his administration, his cozying up to tyrants, all seem trivial in retrospect after months of media focus on a single, life-engulfing phenomenon. “Never again” becomes Biden’s mantra, and in this context it’s a more powerful one than “four more years.”

On November 3, a relatively normal national election is held, though there are a record number of mailed ballots and a lower than average voter turnout.

This is probably the best-case scenario for Biden. The pandemic laid bare Trump’s worst weaknesses as a president; his inability to distinguish fact from his own selfish fantasies, his utter lack of prudence and circumspection in his speech, his inability to credibly empathize or to inspire, his tone-deaf theatrics, his profound ignorance of science, his alarming vindictiveness toward those who don’t pay him fealty. To name a few. Whatever Trump may be, he is no leader in the sense that even the most cynical of us understands the term, and this crisis has made that blindingly clear. It speaks volumes that Pence looks statesmanlike by comparison.

Biden has his own weaknesses in some of these areas, but in this scenario he can leverage the recent experience of a national disaster to call for unity around constructive change, a more rational health care system, a return to respect for expertise and to a competent, effective federal government without the excesses of Sanders-style populism or the absurd, daily self-sabotage of Trump.

Will that be enough to move the swing states? Hard to say. Give a slight edge to Biden.

Scenario B: The pandemic continues to accelerate into the early summer before it begins a year-long decline, or crests in May but then re-surges in the fall, beginning a new wave that is predicted to peak in December. The markets tank again, quarantines and school closures are re-imposed. Unemployment surpasses historic highs, and another round of stimulus legislation becomes necessary. Despite efforts to encourage voting by mail, the national vote in early November is deeply suppressed by social distancing and fear.

Though Trump’s main calling card -the economy- would be in tatters, this scenario heavily favors Trump. Low turnout suppresses minority and youth votes. He can time a new round of cash remittances to the unemployed to arrive just before election day. Most importantly, Americans tend not to vote presidents out of office in times of crisis. Think Woodrow Wilson, FDR, Truman. Continuity, even of the mediocrity that Trump represents, seems more desirable than changing horses in the middle of a hurricane.

Some Democrat friends think that the pandemic is the final nail in Trump’s political coffin, that it’s an act-of-God impeachment, that stripped of an historically low unemployment rate as the main justification for his presidency, he’s lost some percentage of the white non-college-educated men who are his hard-core constituency. But despite all, his approval numbers are rising, and Americans have the charming, homely instinct in times like these to forgive mistakes and focus on even modest successes. Trump will be the beneficiary of all that.

The likely reality of the effect of the pandemic on national politics in this election year probably falls somewhere in between these two scenarios. But the terribly sobering fact is that the course of a disease may have more influence on the outcome of our presidential election than any other single factor, even the crucial question of whether we want competence and foresight in our head of state, and what competence and foresight should look like in a time of crisis.