WASHINGTON – With both the House and Senate back at the Capitol this week for the first time since lawmakers left town for their summer recess, Congress is facing four looming deadlines that highlight just how hard it is to run the federal government when the two parties don’t want to work together.

Congress might not reflect the nation perfectly, but the elected officials and their staffs from across the country make for a good microcosm of the left-right divide among Americans. And in the halls of the Capitol complex, that rift is visible on the faces of lawmakers and their aides: Almost invariably, Democrats wear face masks while Republicans do not.

“Just like in the country, there seems to be a partisan divide in who does and does not wear masks,” said Rep. Kim Schrier, a Democrat who represents a district that stretches from Wenatchee to the Seattle suburbs. “A year and a half into this pandemic, the fact that we are still fighting about things like masks is incredibly frustrating.”

The Capitol is also a faithful facsimile of the confusing patchwork of rules and recommendations on mask wearing – and their inconsistent enforcement – across jurisdictions around the United States.

After the Centers for Disease Control and Prevention on July 27 recommended everyone wear masks indoors in areas of high COVID-19 transmission, the House’s attending physician issued guidance that everyone in the Capitol complex should wear a medical-grade mask.

In response, Minority Leader Kevin McCarthy of California, the top House Republican, called the return of masks a “threat” and accused Democrats of wanting “to live in a perpetual pandemic state.”

Soon after, House Speaker Nancy Pelosi, D-Calif., reinstated a mask requirement for the House floor, but that rule doesn’t apply on the Senate side of the Capitol. Individual House and Senate lawmakers also have broad authority in their respective offices, and most Republicans have not observed the attending physician’s guidance.

The divide hasn’t necessarily kept Republicans and Democrats from working together.

On their way to the Senate floor for a vote on Tuesday, a maskless Sen. Jim Risch, R-Idaho, continued his conversation with masked Sen. Chris Coons, D-Del., as the two men boarded an elevator together. On Wednesday, masked Sen. Amy Klobuchar, D-Minn., shared a joke with Sen. John Barrasso, R-Wyo., as he got off the Senate subway without a mask on.

D.C. Mayor Muriel Bowser also reinstated an indoor mask requirement on July 29, but the Capitol and its attached office buildings aren’t subject to those rules that apply everywhere else in the nation’s capital.

An array of signs posted around the Capitol and the adjacent office buildings connected to it by tunnels do little to clarify things.

“All individuals should wear a well-fitted, medical-grade filtration mask when they are in an interior space and other individuals are present,” one common sign reads, citing the attending physician’s guidance. Yet others, citing the same source, declare “masks not required if fully vaccinated.”

Schrier, a second-term lawmaker who worked as a pediatrician until entering the House in 2019, had just returned to her office across the street from the Capitol on a humid D.C. day and admitted she was sweating under her black KN95 mask.

“I do not like wearing this thing,” Schrier said. “Nobody likes them, but it does keep us healthy. It kept our kids healthy and still does, and it’s a pretty easy thing to do. There’s more important matters we should be debating.”

Those matters include two deadlines with big stakes for the U.S. economy, and the partisan divide on Capitol Hill is threatening to throw a wrench in the works.

If Congress doesn’t pass a bill to fund the federal government by Sept. 30, the end of the fiscal year, the government will shut down. Separately, the House and Senate need to pass a bill by mid-October to raise the debt limit – the amount of money the federal government can borrow – to avert a default that could devastate the nation’s economy.

The Democratic-majority House passed a short-term government funding bill late Tuesday night on a party-line vote, but senators are expected to insist on changes to the legislation in a process that could come down to the wire. With Republicans opposing the spending bill, Democrats’ paper-thin majorities in both chambers are testing the party’s unity.

The GOP is also signaling its members won’t support a bill to increase the debt ceiling, a routine process that has usually been done with bipartisan support. Both parties already have their eye on next year’s midterm elections and are aiming to use the standoff to hurt their opponents’ chances of reelection.

Democrats, meanwhile, have combined the debt ceiling legislation with funding for disaster relief and resettling Afghan refugees, hoping to make Republicans choose between supporting the bill or taking a politically risky “no” vote.

That political brinkmanship is happening while Democrats are trying to iron out some major differences within their own party over two bills that together represent almost the entirety of President Joe Biden’s agenda: an infrastructure package that already passed the Senate with bipartisan support and a massive spending bill that has zero GOP support.

The bipartisan bill – which would authorize about $550 billion in new spending on roads, bridges and other “hard infrastructure” – is up for a vote in the House on Monday. But progressive Democrats say they will only support that legislation if party leaders guarantee the other bill, which would spend as much as $3.5 trillion on a vast array of programs, will pass in the Senate.

While 17 GOP senators voted for the narrower infrastructure bill – including Risch and fellow Idahoan Mike Crapo – most House Republicans have signaled they won’t vote for the bipartisan package unless they’re assured the bigger bill won’t pass, the opposite of the guarantee progressives are seeking.

Correction: The original version of this story mistakenly referred to Sen. John Barrasso, R-Wyo., by the wrong name. Retired NHL goaltender Tom Barrasso played briefly for the Ottawa Senators, but he was never a U.S. senator.