The federal government appeared headed toward a partial shutdown at 12:01 a.m. Saturday, as President Trump insisted that a new spending bill include funding for his proposed “big, beautiful” wall along the southern border.

Democratic leaders said they wouldn’t oblige, and it wasn’t clear that the GOP-controlled Congress could whip up enough votes for a measure that Trump would sign.

By midday Friday, the White House had not spelled out details of the shutdown impact.

There were two brief shutdowns earlier this year. But this shutdown would be narrower in scope than past ones because Congress has already passed spending bills for a number of departments. In addition, Social Security, Medicare, and Medicaid would likely keep running because they are not funded through the annual appropriations process. VA services would also likely be uninterrupted.

Which federal departments are funded?

Congress already passed bills funding the Departments of Defense, Energy, Labor, Health and Human Services, and Veterans Affairs — as well as the legislative branch — through Sept. 30, 2019. Trump signed those appropriations into law, so these departments should not be affected. In addition, the U.S. Postal Service will function as normal, as it gets almost all of its funding from sales of postage and other services.

The Department of Defense is already funded for this fiscal year and is not affected by the potential government shutdown. DoD employees will report to work as normal, said Angelique N. Smythe, spokesperson for Joint Base McGuire-Dix-Lakehurst in South Jersey. “Non-DoD federal entities on the base may be affected by the shutdown.”

Which federal departments don’t have secured funding?

In limbo because of the dispute between the president and Congress is funding for the Departments of Agriculture, Commerce, Justice, Homeland Security, Interior, State, Transportation, and Housing and Urban Development, as well as several smaller agencies.

Though the Coast Guard and the Transportation Security Administration are under the Department of Homeland Security, those agencies are considered vital to national security and would continue operating. In a 2013 shutdown, for instance, TSA personnel still screened travelers at Philadelphia International Airport, and the Coast Guard monitored the waterways.

Nationally, an estimated 420,000 employees, including those in federal law enforcement, will work without pay in a shutdown, while 380,000 others deemed nonessential (though the government does not officially use that word, it’s the colloquial term) will be furloughed.

What about Philly’s famous historical sites?

If you’re planning a trip to Independence Hall, the Liberty Bell, or Valley Forge National Historical Park, check the news first. Those sites are managed by the National Park Service and usually are among the earliest and most visible federal services to close or offer curtailed access. Other sites in the city, and the Independence Visitor Center, are not funded by the federal government and should operate normally. Washington Crossing Historic Park in Bucks County should not be shuttered — the park is operated by the Pennsylvania Department of Conservation and Natural Resources and a nonprofit group. So the annual Christmas reenactment of Washington’s attack on Trenton should be uninterrupted.

Are you a federal employee?

During a shutdown in 2013 that lasted for 16 days, nearly 50,000 federal employees in the Philadelphia and Camden metropolitan areas were furloughed without pay.

In New Jersey, nearly 4,000 civilian employees at the joint base and the National Guard were furloughed for several days, though they returned to work when the Defense Department determined they were necessary for their contributions to military readiness.

Congress later authorized back pay for the 850,000 total workers who were furloughed nationwide.

Staff Writer Tommy Rowan contributed to this article.