Updated

No two words invoke more fear in the federal workforce than "government shutdown."

And that's precisely what the government could face in the coming weeks if President Obama isn't able to come terms with the House and Senate on a blueprint to run the federal government for the rest of this fiscal year.

But what does that mean?

On its most base level, a shutdown means that most of government can't operate -- at all. In other words, if there is no money to pay for anything, the government comes to a screeching halt.

Where does it start?

There's no money for the Pentagon. There's no money to issue passports. Social Security offices would shutter. No veterans' benefits go out the door. National parks are closed. Museums on the National Mall are locked. People eligible to enroll in Medicare would be declined.

The Food and Drug Administration would halt clinical trials. A shutdown would prevent the hiring of new federal employees. The EPA would cease cleaning up toxic waste sites. And, the Internal Revenue Service would be unable to collect taxes.

The impact of a government shutdown is particularly acute in Washington since so many federal workers, ranging from those employed at the State Department to those at the Bureau of Indian Affairs, can't get to their jobs.

But it also means that federal workers across the country or abroad can't come to work, either. And no one gets paid.

For their part, Congressional Republicans have said repeatedly they don't want a shutdown. But the White House says that federal agencies are prepped to work on limited schedules. That's a scenario where only "essential" employees would report if the sides can't break the impasse.

The federal government has closed before in 1981, 1984 and 1990. But the multiple, partial government shutdowns of 1995-96 serve as the baseline against which all other closures are measured against.

In that instance, President Clinton and Congressional Republicans battled each other for weeks over spending priorities. The GOP had just seized control of the House for the first time in decades, and House Speaker Newt Gingrich, R-Ga., led a band of freshman in a pitched fight against the Clinton administration over what the government should spend its money on.

Such a massive shutdown today could have greater impact as the federal government is much larger than it was in the mid-1990s. After Sept. 11, 2001, the government went through a massive reorganization as it launched the Department of Homeland Security.

Even if there is a closure, some federal agencies will remain open, regardless of what Congress and the president decide.

Despite running deficit chasms, the U.S. Postal Service hasn't relied on a congressional appropriation of money in decades. It's said ‘the mail must go through.” And it will, as the Postal Service is self-sufficient.

Just don't expect any Social Security checks to be in it.