Washington • Congress has until Friday evening to pass a spending bill to keep the government running but congressional leaders are still unsure if they can muster the support to pass a budget. Washington frequently comes to the brink of a shutdown, though Congress mostly passes an eleventh-hour plan that kicks the can down the road for a few weeks or months. But sometimes, as in 1995 and 2013, the impasse is too much to overcome.

Will the government actually shut down?

Democratic leaders are mostly opposed to passing a spending bill that doesn’t offer a fix for hundreds of thousands of “Dreamers” — the immigrants who were brought here illegally as children. President Donald Trump ended the Deferred Action for Childhood Arrivals program last year, though left open a transition period for Congress to act. It hasn’t.

Republicans, who control the House and the Senate (and the White House, of course), are hoping to whip enough votes for a short-term budget, though some conservative members are balking and in the Senate, Republicans only control 51 seats and GOP Sen. John McCain is absent for cancer treatments. The Senate needs 60 votes.

Congressional leaders are hopeful they can get there, and the White House, too. But there are only so many votes available.

What happens if Congress can’t make a deal?

If there’s no budget, come Saturday morning, hundreds of thousands of “non-essential” federal workers would be furloughed, though the weekend timing may lessen the pain if Congress can come to an agreement before the workweek starts. If there’s still no deal by Monday, most federal offices would remain closed, and most non-emergency and non-health related services shuttered.

Who still works during a shutdown?

Military and national security operations would continue and federal law enforcement officers would still be expected to show up. Food inspectors for the Agriculture Department would keep working, as would Transportation Safety Administration officials and those government employees who process Social Security checks and payments for Medicaid and Medicare.

Federal courts are likely to stay open for the short term. Postal service would continue as well because it doesn’t operate under congressional funding.

Unlike during past government closures, the Interior Department has outlined ways for national parks, federal lands and public memorials, like the World War II and the Lincoln monuments, to remain accessible to visitors. Campgrounds and most concessions would close.

What closes?

All other “non-essential” and non-health related services are likely to be closed. That includes help lines run by the Internal Revenue Service, new enrollments by the National Institutes of Health, processing of passports and visas and new mortgage approvals by the Federal Housing Administration. The Smithsonian museums would shutter, too.

Some rural development programs and state block grant functions would cease. Federal buildings, for the most part, would remain locked. Government websites would remain up but not maintained.