Updated

Washington is warning Americans about the likely effects of a government shutdown should lawmakers fail to strike a deal to fund the government before it runs out of money Oct. 1 -- from immediate furloughs for thousands of federal workers and cutbacks in veterans’ care to possible, longer-term national security risks.

The warnings are part of a 19-page advisory from Capitol Hill that makes clear federal agencies must cease operations under the so-called Antideficiency Act -- except in emergency and other extreme situations.

And while federal programs and agencies that directly perform national security functions have historically been exempt, the advisory states that closing parts of the federal government indirectly related to the national “security apparatus … could result in increase risked to the nation.”

The advisory suggests that shuttered emergency services and support operations would delay the United States in recovering from a crisis or emergency.

Even the perception of a U.S. government shutdown could have negative security implications “as some entities wishing to take actions harmful to U.S. interests may see the nation as physically and politically vulnerable,” the advisory states.

Furthermore, some security experts argue that the longer the shutdown, "the more at risk the nation becomes as enemies of the U.S. may seek to exploit perceived vulnerabilities," according to the advisory.

The advisory was prepared by the nonpartisan Congressional Research Service and is based on several sources – including White House instructions to federal agencies, revised after April 2011 when a budget stalemate between Congress and President Obama threatened a shutdown. Another is a review of what happened during the government’s most recent shutdown, in the mid-1990s.

While President Obama and essentially every Capitol Hill lawmakers have expressed their unwillingness to force a shutdown next month -- the deadline is just days away with no sign of a deal between the Democrat-controlled Senate and the Republican-led House, which Obama would have to approve.

And the situation -- which typically gets resolved before the deadline -- is further complicated this time by the House voting Friday to pay for everything in the federal budget but the president’s signature health care law, known as ObamaCare.

“We had victory today,” House Speaker John Boehner said after the vote. “The House has listened to the American people. Now it's time for the U.S. Senate to listen.”

Such a plan has effectively no chance of passing the Senate and undoubtedly would be vetoed by Obama, similar to when President Clinton vetoed Congress’ plan in 1995, triggering the country’s longest and most-recent shutdown.

The shutdown lasted 21 days -- from December 16 to January 1996 -- resulting in the furlough of several hundred thousand federal employees and had a negative impacted that rippled across several sectors of the economy.

President Obama said Saturday: “There’s … a faction on the far right of the Republican Party who’ve convinced their leadership to threaten a government shutdown if they can’t shut off the Affordable Care Act. Some are actually willing to plunge America into default. … Well, that’s not happening.”

Among the other likely and immediate impacts of the shutdown would be the closure of hundreds of national parks, tens of thousands of daily visa applications going unprocessed and hiring freezes for federal law enforcement agencies, according to the advisory.

A prolonged shutdown has the potential to shutter federal courts and other, more essentials services. And Obama warned Saturday that military personnel, including those deployed overseas, will not get their paychecks on time.

Earlier this week, Office of Management and Budget Director Sylvia Burwell sent a letter to federal agencies ordering them to make contingency plans for a possible shutdown.

The letter stated Congress still has enough time to prevent a lapse in funding but "prudent management" requires that the government get ready.

The letter was also sent as a second Washington battle looms – negotiations on raising the federal debt ceiling before the country defaults on its debts.

“The United States of America is not a deadbeat nation,” the president said Saturday in his weekly address. “We are running out of time to fix this.”