New year, no budget: How Washington works!

NEW YORK (CNNMoney.com) -- Happy fiscal new year, Uncle Sam. Granted, there's not much to celebrate yet.

That's because lawmakers are not even halfway done finalizing the roughly $3 trillion federal budget for fiscal year 2010, which starts on Thursday.

The 2010 federal budget consists of 12 appropriations bills that need to be passed by both the House and the Senate. And then they need to work out their differences on each of those appropriations.

So, to prevent a complete government shutdown on Oct. 1, lawmakers will need to do what they've done for all but four of the past 33 years: Pass a so-called continuing resolution, which will keep money flowing to federal departments and agencies so they won't have to turn out their lights.

The House on Friday passed a continuing resolution that would fund the government through the end of next month. The Senate is likely to take up the measure next week, although it's not clear yet which day, according to an aide in the office of Majority Leader Harry Reid, D-Nev.

The fallout of not passing a continuing resolution would be no small matter.

"Government shutdowns have necessitated furloughs of several hundred thousand federal employees, required cessation or reduction of government activities, and affected all sectors of the economy," according to a Sept. 9 report from the Congressional Research Service.

The longest government shutdown ever took place during the Clinton administration and ran from Dec. 16, 1995. to Jan. 6, 1996.

The consequences of not putting the budget to bed by the time a new fiscal year begins aren't nearly as harsh, but they're not insignificant.

"Agencies don't know what they have to spend for fiscal year 2010. It makes planning for agencies uncertain and it hampers good management," said Charles Konigsberg, chief budget counsel of the Concord Coalition, a deficit watchdog group.

That the House's continuing resolution only runs through the end of October doesn't actually mean lawmakers would wrap up the budget process by then, although that is the hope.

"Generally they do a series of short-term continuing resolutions to keep the pressure on the appropriators to finish the bills," Konigsberg said.

But because everyone expects Congress to be in session through most of December because of the many battles to come over health reform, it may be Christmas before any real resolution on the 2010 budget is locked in.

In the meantime, lawmakers are likely to face another high-stakes vote to raise the country's debt ceiling. That's because with the government borrowing record amounts of money this year, the expectation is that the nation's current debt ceiling of $12.1 trillion will be pierced sometime this fall.