House Democrats introduced a sprawling coronavirus rescue bill Tuesday that would direct more than $3 trillion to state and local governments, health systems and a range of other initiatives, setting up a huge clash with Senate Republicans and the White House over how to deal with the sputtering economy.

The legislation also would send a second round of stimulus checks to millions of Americans and include more funding for the Postal Service. Not every component of the measure would include more government spending. Some parts would aim to address the coronavirus pandemic in other ways, such as by requiring passengers to wear masks on airplanes and public transit.

Republicans rejected the legislation even before they saw it, describing it as a liberal wish list that would go nowhere in the Republican-led Senate. For example, the bill would suspend a tax provision for two years that limits tax breaks for upper-income households in high-tax states, something Democrats have tried to change for several years. Senate Majority Leader Mitch McConnell (R-Ky.) said he was at work on crafting liability protections for businesses instead. “This is not a time for aspirational legislation,” McConnell said.

The massive new Democratic bill was assembled by House Speaker Nancy Pelosi (D-Calif.) and her top lieutenants without input from Republicans or the Trump administration. It’s less an opening bid in a bipartisan negotiation than an expression of House Democrats’ priorities that they hope will resonate with the public as the nation suffers through the worst economic calamity since the Great Depression.

As health officials and economic advisers warn that the pandemic and economic fallout are likely to drag on through the summer and at least into the fall, lawmakers from both parties are watching how the government’s response to the virus could affect the November elections.

The U.S. economy lost 20.5 million jobs in April, pushing the unemployment rate up to 14.7 percent. Many experts think the rate will go even higher in the coming months as many Americans remain unsure about returning to work or spending money as the government continues to try to contain the pandemic.

“We must think big for the people now, because if we don’t it will cost more in lives and livelihood later,” Pelosi said at a news conference. “Not acting is the most expensive course.”

The 1,800-page legislation, which the House is expected to vote on Friday, would devote nearly $1 trillion to state, local, territorial and tribal governments, and establish a $200 billion “Heroes Fund” to extend hazard pay to essential workers. It also would send a second — and larger — round of direct payments to individual Americans, up to $6,000 per household.

Other parts of the measure would increase nutrition assistance benefits by 15 percent and provide $175 billion in housing assistance, among other things. A $600 weekly increase in unemployment insurance would be extended through January, and the bill directs an additional $75 billion for coronavirus testing and contact tracing.

Other provisions include $25 billion for the U.S. Postal Service — a frequent target of attacks from President Trump — and a new requirement for passengers and employees on airlines, public transit systems and Amtrak trains to wear masks. Protections are included for legitimate cannabis-related businesses, and there is $3 billion to increase mental health support and $400 million to help the Census Bureau deal with coronavirus-related delays in the 2020 Census.

The Democrats’ legislation also includes provisions to ensure that all voters can vote by mail in the November election and all subsequent federal elections, an idea that Trump and many Republicans have rejected because they say it invites fraud.

It would be Congress’s fifth coronavirus relief bill, building on the $2 trillion Cares Act passed in late March. But while the first four bills were the result of urgent bipartisan compromise in the early days of the pandemic, now the two sides aren’t even talking and are moving in radically different directions. It’s unclear when they will come together to produce another bipartisan response, but some Republicans suggested it may not be anytime soon.

Asked Tuesday whether the Senate needs to pass a bill before Memorial Day, Sen. Lindsey O. Graham (R-S.C.) said, “Oh, God, no.” Many Republicans argue that after spending about $3 trillion already in the laws passed thus far, they need to pause and see how those programs are working before doing anything further.

Speaking on the Senate floor on Tuesday, McConnell described the House Democratic legislation as “a big laundry list of pet priorities.” He said it was “exactly the wrong approach.”

McConnell said Senate Republicans would be producing legislation to offer legal liability protections to businesses, health-care providers and the makers of protective gear to prevent what he warned could be “a second epidemic of frivolous lawsuits.”

Many business groups have asked for this liability protection to serve as a shield against lawsuits from employees who might become infected while at work.

Pelosi has said Democrats are not interested in offering liability shields to businesses, arguing that businesses can avoid lawsuits by following appropriate safety protocols. The Democratic bill requires the Occupational Safety and Health Administration to issue a strong national standard within seven days requiring all workplaces to implement infection control plans and prevent retaliation against workers who report problems.

Senate Minority Leader Charles E. Schumer (D-N.Y.) lashed out at Republicans for their unwillingness to take further action. “What is it going to take for Mitch McConnell to wake up and see that the American people need help and need it now?” Schumer asked at a news conference.

Trump has sounded more open to additional legislation. Asked Monday about a second round of direct payments to individuals that’s part of the House Democrats’ bill, he said, “Well, we’re talking about that with a lot of different people. I want to see a payroll tax cut. I want to see various things that we want. I want the workers to be taken care of. But we are talking about that. We’re negotiating with the Democrats. We’ll see what happens.”

Democrats say that the White House is not, in fact, negotiating with them. And the payroll tax cut that Trump has repeatedly talked about is probably a non-starter on Capitol Hill, with even Senate Republicans rejecting it.

However, there are some programs now in effect that Republicans are eyeing changes to, which could help force congressional action in June, if not before. Two-month loans issued under the small-business Paycheck Protection Program, created as part of the Cares Act in late March, will begin to expire, and some Republicans would like to see their time period extended. The $600 billion program itself, which already ran out of money once, forcing Congress to step in and add more in its most recent coronavirus bill last month, could also run short of funding again.

Mike DeBonis contributed to this report.