“We have a different value system about what voting means to a democracy. And clearly, we want to remove all obstacles to participation,” Speaker Nancy Pelosi (D-Calif.) told reporters on her own call later Thursday. “No surprise that [McCarthy] might dismiss opening doors of participation as something that is a plus, especially in a time of pandemic.”

The fierce pushback from McCarthy comes on the heels of President Donald Trump urging Republicans on Twitter Wednesday to “fight very hard when it comes to statewide mail-in voting.” Trump — who has suggested the practice could undermine GOP political prospects — has also claimed that mail-in voting is “corrupt.”

McCarthy echoed a similar sentiment Thursday, saying “there’s also a lot of fraud” that can happen with mail-in voting and raising concerns about ballot harvesting. Other Republicans, such as Rep. Greg Walden of Oregon, have argued that it would be a logistical challenge to force states to switch to a nationwide vote-by-mail system.

Although Trump has claimed that mail-in voting is rife with corruption, there is no evidence to suggest that voter fraud exists on a wide scale anywhere in the election system. The president himself cast a mail-in ballot in Florida as recently as last month for that state's primary election.

With coronavirus cases soaring, mail-in voting has become a new political flashpoint — particularly after the electoral mess in Wisconsin this week, which saw significantly reduced polling places and long lines of voters with face masks.

Democrats want to include money for state vote-by-mail efforts in their next big emergency rescue package, pointing out that normal elections violate the social distancing guidelines from the federal government and could pose a major public health risk.

But the effort has run into a wall of resistance from Trump and Republicans, who say it’s something that should be left up to the states — not the federal government. The issue could prove to be a major sticking point in future negotiations.

Washington secretary of state Kim Wyman, a Republican who supports vote-by-mail efforts, said Thursday members of Congress need to work together on expanding access to voting in a bipartisan way.

“It’s disappointing that anyone in leadership is critical of either the security or the accessibility of our elections by accusing voters or election officials of perpetrating voter fraud or voter suppression,” Wyman said. “With this pandemic we have to get past partisanship.”

McCarthy said Pelosi tried to push for mail-in voting — as well as some other Democratic priorities — during negotiations on the last economic rescue package and rebuffed her.

“I told her this is not the place or time for it,” McCarthy said. “Let’s focus on this virus, let’s cure the problem, let’s get our economy back on its feet and then we can debate about elections.”

Heather Caygle, Marianne LeVine and Myah Ward contributed to this report.