More than 73 million Americans have already voted using postal or absentee ballots, and Mr Trump and Mr Biden are trying to energise the millions more who will vote in person on Tuesday.
While the election day vote traditionally favours Republicans and early votes tend toward Democrats, the coronavirus pandemic, which has killed more than 227,000 people in the United States, has injected new uncertainty about the make-up of the electorate.
Mr Trump and Mr Biden will appear in Tampa hours apart on Thursday, visiting the western end of the state’s Interstate 4 corridor, the area known for its rapid residential growth, sprawling suburbs and status as a hard-fought battleground during presidential elections.
The visit comes as Mr Biden has framed his closing argument to voters on responsible management of the Covid-19 pandemic and Mr Trump promises that the nation is on course to “vanquish the virus” even as it sets records for confirmed new infections.
“Even if I win, it’s going to take a lot of hard work to end this pandemic,” Mr Biden said on Wednesday during a speech in Wilmington, Delaware. “I do promise this: we will start on day one doing the right things.”
Mr Trump spent Wednesday in Arizona, where relaxed rules on social distancing made staging big rallies easier.
Thousands gathered in close proximity without wearing masks — a trend that was expected to continue through more than a dozen events in the final sprint to election day.
Mr Biden, meanwhile, heads later in the week to three more states that Mr Trump won in 2016, Iowa, Wisconsin and Michigan, where he will hold a joint Saturday rally with former president Barack Obama.
The pandemic’s consequences were escalating, with deaths climbing in 39 states and an average of 805 people dying daily nationwide — up from 714 two weeks ago.
The sharp rise sent shockwaves through financial markets, causing the Dow Jones Industrial Average to drop 900-plus points.
Mr Trump, who frequently lauds rising markets, failed to mention the decline on Wednesday.
But economic growth figures for the summer quarter were strong, and Mr Trump declared during a rally in Bullhead City, Arizona: “This election is a choice between a Trump super-recovery and a Biden depression.”