Washington has lurched from one budget crisis to another for most of the past three years after Republicans captured control of the House in 2010. Many of those GOP lawmakers were elected on platforms of repealing the Affordable Care Act and cutting the size of the federal government.

An estimated 180,000 Marylanders are expected to enroll in health coverage through a new insurance marketplace created under the law that will open for business on Tuesday.

The House effort on Saturday put the political onus back on Senate Democrats to either hold firm to their resistance to Obamacare alterations or to pass another funding bill.

"The American people don't want a government shutdown and they don't want Obamacare," House Speaker John Boehner said in a statement. "We will do our job and send this bill over, and then it's up to the Senate to pass it and stop a government shutdown."

Both parties have tried to set the other up to take the blame if the government shuts down.

"The House is taking action to keep the government running and protect the men and women in our military in case the Senate and president refuse to negotiate and shut down the government," said Rep. Andy Harris, Maryland's only GOP lawmaker in Congress.

Meanwhile, White House press secretary Jay Carney said in a statement, "Today Republicans in the House of Representatives moved to shut down the government. Any member of the Republican Party who votes for this bill is voting for a shutdown."

The debate left agencies, employees and contractors bracing for a shutdown.

Alan Chvotkin, executive vice president and counsel to the Professional Services Council, said contractors have been advised to continue performing work if the government shuts down unless specifically told not to.

"If we don't get [a deal] by Tuesday and it goes through the balance of that week, more and more contracts will be identified and more employees will be furloughed," said Chvotkin, whose group represents companies in Maryland and elsewhere.

"The longer it goes, the wider that wedge becomes," he added.

Maryland is home to a robust and growing federal contracting community. The Maryland Department of Business and Economic Development estimates the number of people who work for federal contractors at 171,000. The federal government awarded about $27 billion in contracts to Maryland businesses in the 2012 fiscal year.

The impact of a shutdown could also be felt in less expected ways. During the 1995 and 1996 closures, the American Red Cross warned of blood shortages, for instance. Federal offices are a major source of worksite blood donations.

And several Baltimore-area schools are carefully eyeing field trips planned to Washington next week.

The John Carroll School in Bel Air will host German high school exchange students for a tour of Washington on Oct. 5. Administrators fear the trip may be cut if the government buildings and museums are shuttered.

"There are a few places these students want to see when they come to the United States — one of those places is D.C., which they see as the core to our country," school spokeswoman Laura Lang said. "It's just a shame that every few months we get to this point."

Baltimore Sun Media Group reporters Krishana Davis and Matthew Hay Brown contributed to this report.

john.fritze@baltsun.com

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Past federal shutdowns

Budget battles in Washington have resulted in shutdowns or partial shutdowns three times since 1990.

October 1990: Congress rejected President Bush's spending plan, shutting down the government over the three-day Columbus Day weekend. Most federal workers were off anyway. An emergency spending bill cleared Congress before dawn Tuesday, and work resumed.

November 1995: An estimated 800,000 federal employees were furloughed during a five-day shutdown that resulted from President Clinton's veto of a stop-gap spending bill and debt limit extension. It ended with a one-month funding extension.

December 1995 to January 1996: The government shut down again a month later for 21 days — the longest in the nation's history. An estimated 284,000 employees were furloughed and another 475,000 worked without pay. The shutdown ended with a short-term spending bill.

Source: Congressional Research Service

pay. The shutdown ended with a short-term spending bill.

Source: Congressional Research Service