Empty tables overlooking Seal Rocks are seen inside the closed Cliff House on Wednesday, October 9, in San Francisco. The 150-year-old oceanside icon was ordered closed Wednesday by the National Park Service for the duration of the partial government shutdown, leaving most of the restaurant's 170 employees without work. The federal government entered a shutdown October 1, furloughing hundreds of thousands of workers. Many government services and agencies remain completely or partially closed. 
Boaters gather to protest the closure of Everglades National Park waters on October 9 near Islamorada, Florida. About a third of the 2,380-square-mile park encompasses Florida Bay and has been closed to Florida Keys guides and recreational fishermen since October 1. 
A camping party at the Dolly Copp campground in Gorham, New Hampshire, on October 9 is told that the park will close on Thursday, October 10, at noon. The privately run campground in New Hampshire's White Mountains National Forest was forced to close ahead of the lucrative Columbus Day weekend because of the federal government shutdown. 
Rick Hohensee holds a "Fire Congress" sign near the House steps on Capitol Hill in Washington on Tuesday, October 8. 
Officers stand at the base of stairs leading to the Capitol Rotunda on Monday, October 7. 
A bull elk appears to stick out its tongue at the closed north entrance to Yellowstone National Park in Montana on October 7 in a photo submitted by iReporter Brad Orsted. Orsted joked the animal was giving its opinion on the government shutdown. 
Tourists take photos at a barricade blocking access to the World War II Memorial in Washington on Sunday, October 6. 
River runners make camp in a dirt parking lot in Marble Canyon, Arizona, after being unable to access the Colorado River at Lee's Ferry on Saturday, October 5. 
A closure sign is posted on the National Mall in front of the U.S. Capitol in Washington on Thursday, October 3. 
Metal gates closed with a chain block the entrance to Kennesaw Mountain National Battlefield Park, in Kennesaw, Georgia on Thursday, October 3. A sign posted on the gates announces the park's closure, citing the government shutdown. 
Tourists take photos of the Statue of Liberty while riding a tour boat in New York Harbor on October 3. The statue is adminstered by the National Park Service and is closed as a result of the government shutdown. 
A single security guard patrols the closed Lincoln Memorial in Washington on October 3. 
A U.S. Capitol police officer walks past a statue of Gerald Ford in the rotunda on Tuesday, October 1. The Capitol is closed to tours because of the government shutdown. 
Barricades around the World War II Memorial in Washington prevent people from entering the monument on October 1. The memorial was temporary opened to veteran groups who arrived on Honor Flights on a day trip to visit the nation's capital. 
World War II veteran Russell Tucker of Meridian, Mississippi, stands outside the barricade as he visits the World War II Memorial in Washington on October 1. 
World War II Veteran George Bloss, from Gulfport, Mississippi, looks out over the National World War II Memorial in Washington, on October 1. Veterans who had traveled from across the country were allowed to visit the National World War II Memorial after it had been officially closed because of the partial government shutdown. 
A park ranger secures a road at the entrance to the Mount Rushmore National Memorial on October 1 in Keystone, South Dakota. 
A sign is posted in the window of an IRS office in Brooklyn notifying that the office is closed due to the government shutdown on October 1. 
A visitor takes a picture of a sign announcing the closure of the Fort Point National Historic Site due to the partial government shutdown on October 1 in San Francisco, California. 
A hand-written sign informs visitors to Faneuil Hall, the nation's oldest public meeting hall, that restrooms are closed as a result of the partial government shutdown in Boston, on October 1. 
Visitors to Independence National Historical Park are reflected in the window of the closed building housing the Liberty Bell, on October 1 in Philadelphia. 
Mark Weekley, superintendent at the National Park Service's Lewis and Clark National Historical Trail, puts up a sign proclaiming the facility closed due to the federal government shutdown, in Omaha, Nebraska, on October 1. 
Hot Springs National Park employee Stacy Jackson carries a barricade while closing Arlington Lawn in Hot Springs National Park in Arkansas on October 1. 
The Washington Monument is seen behind a chain fence in Washington, on October 1. 
A National Park Service ranger finishes putting up a sign indicating all facilities at the Martin Luther King Historic Site are closed to the public in Atlanta, on October 1. 
A Capitol police officer walks through the empty Capitol Rotunda, closed to tours during the government shutdown on Capitol Hill in Washington, on October 1. 
An employee at the Springfield Armory National Historic Site in Springfield, Massachusetts, puts up a sign on October 1, to notify visitors that the site is closed because of a government shutdown. 
A U.S. Park Service police officer stands at the closed Martin Luther King Jr. Memorial on the National Mall in Washington on October 1. 
A man looks into the closed Smithsonian National Air and Space Museum in Washington on October 1. 
A National Parks Service ranger posts a sign on the doors of the historic Ebenezer Baptist Church in Atlanta on October 1 notifying visitors that the church is closed. 
A U.S. park ranger places a closed sign on a barricade in front of the World War II Memorial in Washington on October 1. 
Park police and Park Service employees close down the Martin Luther King Jr. Memorial on the National Mall on October 1. 
A sign informs visitors that the Suresnes American Cemetery and Memorial, west of Paris, is closed because of the shutdown on October 1. 
A man walks past a sign noting the closure at the Cuyahoga Valley National Park in Valley View, Ohio, on October 1. 
Members of the U.S. National Park Service close the Lincoln Memorial on the National Mall in Washington on October 1. 
A U.S. park ranger posts a closed sign at the Lincoln Memorial on October 1. 
A sign alerting visitors that the National Gallery of Art is closed stands outside the building on October 1. 
People look at a sign announcing that the Statue of Liberty is closed in New York on October 1. 
Fencing around the World War II Memorial prevents people from entering the monument on the National Mall in Washington on October 1. 
Signs taped on museum doors alert visitors that the National Museum of American History in Washington is closed on October 1. 
A U.S. park service police officer stands guard at the entrance of the closed Lincoln Memorial on October 1. 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
- In six days, the United States government's borrowing authority will be exhausted
- Mark Patterson: A U.S. default could set in motion a financial crisis of global scale
- He says "default deniers" in the GOP are overlooking serious risks and problems
- Patterson: Default would have ripple effect on stock market, businesses and economy
Editor's note: Mark A. Patterson is a senior fellow at the Center for American Progress, a liberal think tank based in Washington. He was chief of staff at the Treasury Department from 2009 to May 2013.
(CNN) -- In six days, the United States government's borrowing authority will be exhausted.
If Congress does not act to extend the debt limit, the Treasury Department will be left with only its cash on hand -- estimated to be about $30 billion -- and whatever revenues it takes in each day.
Because the government is running a deficit, available cash will be insufficient to cover the millions of payments the Treasury makes each day -- to men and women in our armed forces, veterans, Social Security and Medicare beneficiaries, federal employees and retirees, businesses that provide goods and services to the nation, and many others.
Even if Congress opts to pass a temporary extension, the threat of default will hang over the economy until a longer-term solution is adopted.
What does this really mean for the economy, and what does it mean for you?
Congress has never in our history failed to extend the debt limit, so no one knows for sure what would happen if, as some Republicans are now advocating, we tried to operate the government with insufficient funds and no ability to borrow.
It has long been the view of economists, business leaders and the Treasury Department that such a scenario could set in motion a financial crisis. Presidents and secretaries of the Treasury of both parties have urged Congress never to take that risk.
Ronald Reagan himself once said, "Unfortunately, Congress consistently brings the government to the edge of default before facing its responsibility. This brinkmanship threatens the holders of government bonds and those who rely on Social Security and veterans benefits. Interest rates would skyrocket, instability would occur in financial markets, and the federal deficit would soar. The United States has a special responsibility to itself and the world to meet its obligations. It means we have a well-earned reputation for reliability and credibility, two things that set us apart from much of the world."
Reagan's view is widely held, but some Republicans -- dubbed "default deniers" -- now argue that the debt limit deadline can be ignored without serious harm. They have urged the President to continue paying interest on the national debt using available cash and then avoid or delay paying other obligations.
Deloitte CEO: Crisis 'catastrophic' 
Markets frustrated by shutdown woes Although it's not possible to disprove either theory, the default deniers overlook an important problem: Paying interest on the debt would not protect the Treasury against what's called "rollover risk." That's the risk that investors would decide, amid the crisis atmosphere generated by a failure to raise the debt limit, to cash out their maturing Treasury bonds instead of reinvesting (or "rolling over") their proceeds into new Treasuries, as they usually do.
This would be reminiscent of the famous bank scene at the end of "It's a Wonderful Life," only on a huge and frightening scale. About $100 billion in Treasury securities mature each week, so if investors decided to put their money elsewhere, Treasury's available cash would be nowhere near enough to cash those jittery investors out.
In those circumstances, the U.S. would default on both principal and interest payments, and the economic consequences would be swift and severe.
To the extent that we were able to continue borrowing, investors would demand higher interest rates on Treasuries. (These rates have already begun to rise as the impasse in Washington has worsened.) Since Treasury rates are benchmarks for other lending, loans for homes, cars and other needs would become more expensive, and it would become harder to qualify to borrow. Consumer and business confidence would suffer.
As in the last financial crisis, falling confidence would have ripple effects, affecting other markets including the short-term lending used by companies to finance themselves. This would all dampen economic growth, which is still not as strong as we would like in the wake of the last crisis.
The stock market would weaken, and retirement savings would dip. And of course unemployment would rise. Meanwhile, the inability to pay the rest of the government's regular obligations in full or on time would be spreading its own hardship across the economy.
There is no way to know how bad these conditions would get or how far the financial contagion would spread, but it seems safe to say that no good could come from tempting such a fate. The question is: Why in the world would we ever choose to take that risk?
Follow @CNNOpinion on Twitter .
Join us at Facebook/CNNOpinion .
The opinions expressed in this commentary are solely those of Mark A. Patterson.
