(CNN) -- Here's a quick Q&A to get you caught up on some of the basics regarding the partial US government shutdown.
1. Why would the government shut down?
Congress has one key duty laid out in the Constitution -- pass spending bills that fund the government. If it doesn't, most of the functions of the government -- from paying the military, to funding small business loans, to processing Social Security checks -- would grind to a slow-motion halt.
2. Why does it have to pass a spending bill in the middle of the year?
It may be the middle of the calendar year. But the government's fiscal year runs from October 1 to September 30.
3. What's the holdup?
House Republicans insist the spending bill include anti-Obamacare amendments. Senate Democrats are just as insistent that it doesn't.
PHOTOS: Agencies affected by shutdown http://bit.ly/18LJwA5
4. How is Obamacare tied to funding the government?
It isn't. But it's being used as a bargaining chip. A group of Republicans, led by freshman Sen. Ted Cruz of Texas, despises the president's signature health care plan so much that it's willing to risk government shutdown or default.
5. What are the objections?
The Patient Protection and Affordable Care Act, the actual name of the law, requires all Americans to have health insurance. Opponents say it'll hurt employers, and it amounts to overreach by the federal government. Some have also criticized the medical device tax that's part of the law, saying that by imposing such a tax, it's basically sending jobs overseas.
6. What's the Democrats' defense?
Democrats say Obamacare protects those with pre-existing medical conditions from being denied health insurance. They also say it brings costs down because those who have health insurance will no longer have to indirectly pay for those who show up in emergency rooms uninsured.
7. What happened with the spending bill over the weekend?
The Republican-dominated House passed two spending bill amendments Sunday morning -- one that would delay Obamacare for a year, and one that would repeal the Obamacare's medical device tax. The bill now goes back to the Senate, where Democrats who control that chamber have consistently said any changes to Obamacare would be a deal-killer.
8. What happens Monday?
The Senate will meet at 2 p.m. ET -- 10 hours before the deadline. It'll "do exactly what we said we would do and reject these measures," says Senate Democratic Leader Harry Reid. "The American people will not be extorted by Tea Party anarchists."
In other words, the Senate will send its version of the bill -- one without any changes to Obamacare -- back to the House.
Rep. Tim Griffin of Arkansas says the Senate is using that old football strategy: running out the clock. "At some late hour, they'll pass something and then they'll say 'Oh my gosh, we've run out of time.'"
9. So, is there any hope?
You could look at the glass-half-full scenarios.
-- Sen. Rand Paul told CBS' "Face the Nation" the two chambers of Congress should go to conference. Such committees are common when both houses pass competing bills and they need to reconcile the differences. Senate Democratic Whip Dick Durbin Durbin said he's open to talking with Republicans "but not with a gun to my head."
-- If the Senate rejects the bill, the House will get back together "in enough time" and send another provision, House Majority Whip Kevin McCarthy told "Fox News Sunday." But he was quick to add, that too will have provisions about Obamacare.
10. If nothing changes, does the government shut down?
Yes, for the first time since late 1995. That one lasted 21 days.
11. How will it happen?
There won't be a thunderclap or clang of bells. First order of business? Draw up a dividing line -- between workers deemed essential or non-essential. Those in the first category will carry on operations. The others will power down until Congress comes to its senses and funds the government.
So, for example, park rangers would start locking up national parks. Most furloughed federal workers are supposed to be out of their offices within four hours of the start of business Tuesday.
12. How many government workers could be furloughed?
Most of the 3.3 million government workers are deemed "essential" -- they'll keep working. But more than 783,000 government employees will sit at home, according to a CNN analysis of contingency plans published by the federal government on Friday. Not all government agencies submitted contingency plans.
13. What will this do to the economy?
Depends on how long it lasts. If it's just a few days, the hit might not be major. But three or four weeks? "(That) would do significant economic damage" -- reducing GDP by 1.4 percentage points for the quarter, says Mark Zandi, chief economist and co-founder of Moody's Analytics.
14. How will this affect me?
In ways big and small. The mail will continue to come. The military will continue to fight. And Social Security
checks will continue to be paid.
But if you need a federal loan to buy a house, you'll have to wait. If you want a gun permit or a passport, that won't happen anytime soon.
15. Will it kill Obamacare?
It probably won't. Most of the money for Obamacare comes from new taxes and fees, as well as from cost cuts to other programs like Medicare and other types of funding that would continue even if the government shuts down.
16. Will the president get paid during a shutdown?
Yes. His salary -- $400,000 -- is considered mandatory spending. It won't be affected.
17. What about House and Senate members?
They'll draw checks too.
18. What does John Q. Public think of all this?
A CNN/ORC International poll that came out Monday found that 46% will blame congressional Republicans if the government closes its doors, with 36% saying the president would be more responsible and 13% pointing fingers at both.
19. Is there any hope if a deal isn't struck by midnight?
If lawmakers reach an agreement by late Monday night, but the funding bill hasn't made it to the president's desk, the government can ignore a short lapse in funding and carry on in good faith knowing that it will. The last time that happened was April 2011.
20. Isn't there another matter -- the debt ceiling?
Ah yes, that's the next battle brewing. Remember that time when you maxed out your credit card? That's what the debt limit is all about. The U.S. is on the verge of maxing out its $16.699 trillion credit card. And the president must ask Congress to raise the country's credit limit. Like the potential shutdown, this is also a Washington-manufactured crisis. And it too is being used for leverage to undermine Obamacare.
But the debt ceiling debacle won't come to a head until October 17. So, let's deal with one showdown at a time.
CNN's Leigh Ann Caldwell, Z. Byron Wolf, Adam Aigner-Treworgy, Laura Koran, Lisa Desjardins and Bryan Monroe contributed to this report.
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