(CBS NEWS)-- Ten hours before parts of the federal government shut down -- unless Congress manages to strike a budget deal -- the Senate will reconvene at 2 p.m. Monday to initiate the final rounds of fiscal ping-pong between the Democrat-controlled upper chamber and the GOP-controlled House.
There's little cause for optimism. After rejecting a budget proposal passed Friday in the Senate that would have kept the government running until Nov. 15, House members countered in the early hours of Sunday with a continuing resolution that would allocate funding until mid-December, but would also impose a one-year delay on key parts of the Affordable Care Act -- a measure Democrats have called a "non-starter."
Senate leaders have said they will never okay a spending bill that defunds President Obama's signature health care act, and Friday's series of procedural votes made that clear: The bill passed along party lines, with a specific vote to strip it of the health care language, even after Sen. Ted Cruz, R-Texas, attempted to mobilize opponents of "Obamacare" with a 21-hour marathon floor speech. Mr. Obama, for his part, has promised to veto any legislation which defunds the health care act.
House Republicans on Sunday slammed the Senate for recessing Friday, charging Senate Majority Leader Harry Reid, D-Nev., with trying to "run out the clock." A spokesman for Reid responded shortly after with a statement vowing to remove from the House legislation any anti-Obamacare language.
"Knowing full well that the Senate would reject their empty political stunts, House Republicans voted to increase the deficit, deny women coverage for critical preventative services like contraception, and deny affordable health care to millions of Americans," said Adam Jentleson in Sunday's statement. "Tomorrow, the Senate will do exactly what we said we would do and reject these measures."
What happens if the government shuts down?
Presumably, then, House Republican leaders face another choice: To assent to the Senate's "clean" spending bill, devoid of any provision that guts Obamacare, or volley yet another unlikely proposal back to the Senate, inching ever closer to the hour of shutdown. The number three House Republican, House Majority Whip Kevin McCarthy, R-Calif., appeared to embrace the latter option in an interview on "Fox News Sunday."
"I think the House will get back together, and in enough time, send another provision -- not to shut the government down, but to fund it -- and it will have a few other options in there for the Senate to look at it again," he said. "We are not shutting down the government."
Appearing Sunday on CBS' "Face the Nation," Sen. Rand Paul, R-Ky., suggested a last-minute conference committee could prevent a shutdown. But on the same show Senate Majority Whip Dick Durbin, D-Ill., said past precedent proves Republicans will only come to the table as it pertains to delaying health care: "We have been trying for more than six months to get the Senate Republicans to agree to a conference committee on the budget. They refuse a conference committee when it comes to our budget."
Durbin said he was "willing to look at" a measure in the House bill that repeals a tax on medical devices -- "but not with a gun to my head, not with the prospect of shutting down the government." Still, he added, he's "afraid" the government will indeed shut down for a period this week -- a reality that has many Americans asking: What next?
Why is this happening - again?
The bill to fund the government this time around has stalled largely because conservatives have tried to seize the legislation as an opportunity to defund or delay the Affordable Care Act from the get-go, though it was an ultimately futile attempt: The driving parts of Obamacare will effectively remain intact unless the entire law is repealed.
Even if Congress doesn't authorize spending by Oct. 1, the government has plenty of other sources of funding to draw from to keep the law in place. A large portion of the health care law is funded with mandatory spending -- which Congress is required by law to keep up unless the law is repealed -- as well as multi-year funds still available in the event of a government shutdown.
But Rep. Marsha Blackburn, R-Tenn., who authored the amendment to delay health care, tried to make the case Sunday on "Face the Nation" that it's a "reasonable request," citing "bipartisan support for the delay."
Paul, meanwhile, argued that President Obama is the one conducting the march toward a government shutdown: "I've said all along it's not a good idea to shut down government... but I also think that it's not a good idea to give the president 100 percent of what he wants on Obamacare without compromise," he said.
Rep. Chris Van Hollen, D-Md., who serves with Blackburn on the House Budget Committee, called the GOP strategy a "total hoax." The Republican budget, he pointed out, actually kept major parts of Obamacare.
"Their budget would not balance if they hadn't kept the Medicare savings," Van Hollen said. "And every penny of the revenues brought in by Obamacare -- including the amount of revenue brought in by the medical device tax -- is what they've got in their budget."
Who will be affected?
If the government shuts down, programs deemed "essential" -- traffic control, airport security, Medicare and food inspections, for example -- will continue to run. But as many as 800,000 federal employees considered "non-essential," including about half of the Defense Department's civilian employees, will be furloughed, with no guarantee of back-pay.
About 20 of the 1,600 national Head Start programs would feel the impact instantly: Grants expiring Oct. 1 would not be renewed, and over time, more programs could be affected. And the Special Supplemental Nutrition Program for Women, Infants and Children (WIC), which provides food and health care referrals to pregnant women and mothers, could be shut down.
Social Security checks and veterans' benefits would likely be held up, since there would be fewer workers to process them. Passport and visa applications could be put on hold, as well as small business and home mortgage lending programs. National parks around the country and Smithsonian museums would be closed.
While monuments in Washington, D.C., would also be closed, the U.S. Capitol building would remain open. Congress is exempted from the furloughs, though some lawmakers have threatened to protest that rule.
If the government does shut down, how long until it's back in business?
Should Congress fail to send the president a bill before midnight on Tuesday, the outcome would impact the economy, though not catastrophically.
There have been brief gaps in government funding before. Congress came close to a shutdown in 2011, averting it at, literally, the 11th hour.
But the last time the government officially went dark was over the Christmas and New Year's holidays in 1995-96, when partisan gridlock similar to what's behind today's frustrations resulted in a 21-day shutdown, the longest federal operations have ever been shuttered. The government also shut down for five days in November 1995, when then-President Clinton and the GOP-led Congress were at odds over government spending.
According to government estimates, the '95- '96 shutdowns cost taxpayers $1.4 billion.
In the 16 other instances dating as far back as 1976, shutdowns ranged from one day to 18. So, long answer short: There's no clear-cut example off of which to springboard, since resolution depends entirely on when lawmakers are finally able to cut a deal.
Assuming Congress - either before or after shutdown - gets past this, it's clear sailing, right?
The current versions of both the Senate and House bills only keep the government afloat until mid-November or December, respectively. Such stopgaps would have to be revisited - with potentially the same dramatic fanfare - as those dates approach.
Additionally, another fiscal deadline lurks in the coming weeks: Last week the Treasury Department announced the federal government will reach its borrowing limit, or "debt ceiling," by Oct 17. Congress must reach a deal to lift the cap before then or cut off the government's ability to borrow any more money, interrupting all manner of federal disbursements and potentially defaulting on the nation's debt.
The last time Congress raised the debt ceiling, in the summer of 2011, the brinksmanship that preceded the vote compelled Standard & Poor's rating agency to downgrade the credit rating of the United States for the first time in U.S. history.
Some lawmakers - mostly Democrats - have cautioned against another round of high-stakes theatrics. But as the Senate continues to balk at Republicans' budget offers, members of the House have already begun to ready their anti-Obamacare efforts for the debt-ceiling fight.
Mr. Obama has repeatedly said he refuses to negotiate over the debt limit given the potentially dire consequences of failing to raise it - an "economic shutdown, with impacts not just here, but around the world," he said Saturday in his weekly address.
Acknowledging the president's position, though, House Speaker John Boehner, R-Ohio, on Thursday retorted: "I'm sorry, but it just doesn't work that way. We're not going to accept this new normal."