WASHINGTON — A showdown is taking shape in Congress over how far Washington should go in expanding voting access to respond to the coronavirus pandemic, with Democrats pressing to add new options for voters and President Trump and Republicans resisting changes they say could harm their election prospects in November.

Democrats are determined to add new voting requirements for November’s general election to the next stage of coronavirus relief legislation, a move that Mr. Trump and Republican leaders have vowed to oppose. But it is one that Democrats believe is necessary and all the more urgent in light of the confusion and court fights surrounding Wisconsin’s elections on Tuesday.

With public health officials encouraging social distancing and staying at home to slow the spread of the virus, the prospect of millions of voters congregating at polling places around the country to cast their ballots this fall appears increasingly untenable and dangerous. But the fight over whether the federal government should require states to offer other options — by allowing voting by mail, extending early voting and instituting other changes to protect voters and voting rights — is emerging as a major sticking point as lawmakers look to pass a fourth emergency aid measure in the next few weeks.

Democrats argue that changes are imperative, and Congress must make them now before it will be too late to put them in place for the November balloting.