Thursday began with optimism that Democrats and Republicans would find a way to pass a spending bill that would avert a partial government shutdown. There was even hope that it would set the stage for an accord on raising the government’s debt limit.

But rancor returned just hours later. On the Senate floor, Democratic Majority Leader Harry Reid asked agreement from all senators to finish voting on the spending bill Thursday night, but Utah Sen. Mike Lee objected to having the votes that quickly and asked that they instead be taken Friday morning. He was supported by Texas Sen. Ted Cruz, fresh off his 21 hour talk-a-thon against Obamacare.

Reid incredulously asked, “Is this some kind of subterfuge to close the government?”

As a result of these objections, the Senate will now vote Friday on deleting the “defund Obamacare” language from the House-passed spending bill.

If supporters of Obamacare get a simple majority (51 votes), then the provision to defund the program will be removed from the legislation. And the new bill will likely have no trouble passing the full, Democratically-controlled Senate. After that, the continuing resolution or “CR,” would go to the House.

The clock is ticking down to a potential government shutdown, but even if a deal is reached to avert the crisis, it's one that will actually cost voters extra money. NBC's Chuck Todd reports.

And then what will the House do?

It’s not clear. When a reporter asked House Speaker John Boehner on Thursday whether he would accept a “clean CR” from the Senate, meaning one that just funds the government at its current levels, he replied, “I do not see that happening.”

He added cryptically, “there will be options available to us.” The House will be in session Saturday and Sunday to deal with the spending bill.

What are possible scenarios if the House rejects the Senate-passed spending bill?

One possibility is that Boehner could try to get Reid and the Democrats to accept a very short-term stopgap bill, and then try to resume his fight over defunding the Affordable Care Act later.

Another scenario would be if the House cannot act and Washington moves one step closer to a government shutdown.

What if the House votes to accept the Senate-passed spending bill?

That would temporarily end the struggle over spending. The president would sign the bill into law and government operations would continue. But for that to happen, House Republicans would have to concede defeat in their attempt to defund Obamacare.

What if the House takes the Senate-passed spending bill and adds other items to it -- even if they have nothing to do with defunding Obamacare?

The Senate then would need to either accept the House provisions or amend the bill by cutting out all the provisions added by the House and then send the bill back to the House – continuing the “ping-pong” process. But with time running short, the deadline for a shutdown would likely be passed by the time anything is agreed to under this scenario.

Could a “sweetener” be added to the Senate spending bill that might satisfy House Republicans even if it doesn’t include the defund-Obamacare provision?

There was some speculation Thursday that perhaps Republicans might agree to pass the Senate spending bill if it included repeal of the medical device tax that is part of the Affordable Care Act.

But White House spokesman Jay Carney flatly rejected that idea Thursday, telling reporters, "Absolutely not."

Are there any other possible outcomes?

At some point the two bodies need to pass identical bills, no matter how long that might take. But continued funding of the government expires Monday at midnight.

Since the Democrats have a majority in the Senate, it’s hard to imagine a bill passing both bodies which in the end would be unacceptable to President Barack Obama.

If a partial federal government shutdown begins on Tuesday is it certain what offices and operations would halt and which ones would continue?

No – all that the Office of Management and Budget will say is that federal agencies “are still in the process of reviewing relevant legal requirements and updating their plans” if there is a shutdown.

The Administrative Office of the U.S. Courts announced Thursday that if a government shutdown begins the federal courts “will remain open for business for approximately 10 business days.”

And based on past experience, government functions essential to public health and safety such as meat and poultry inspection will continue even if there’s a partial shutdown. But national parks and monuments would be closed.

How does the upcoming struggle over raising the government’s borrowing limit relate to this week’s fight over a government shutdown?

The spending bill and the debt limit are separate issues and will require separate votes by Congress.

But the discord over the spending bill doesn’t bode well for agreement on increasing the debt limit.

Treasury Secretary Jack Lew told congressional leaders Wednesday that the debt limit -- which is now about $16.7 trillion -- will be reached no later than Oct. 17. At that point, the Treasury won’t have enough in daily tax receipts and cash on hand to meet all its obligations such as paying contractors and paying retirement benefits. That raises the specter of the federal government defaulting on its debt -- which would throw financial markets into turmoil.

What items do House Republicans want to attach to a bill to increase the debt limit?

House Republicans may try to attach an array of policy proposals to the bill to increase the debt limit.

One would be a one-year delay in the implementation of Obamacare.

Other possible ideas include approval of the Keystone XL pipeline, measures to spur offshore oil and gas production, a halt to greenhouse gas regulations issued by the Environmental Protection Agency, and an increase in means-testing in the Medicare program.

But Obama said Thursday that he wouldn’t bargain with the Republicans over the debt limit. “We are the world's bedrock economy, the world's currency of choice. The entire world looks to us to make sure that the world economy is stable,” he said. “You don't mess with that. And that's why I will not negotiate on anything when it comes to the full faith and credit of the United States of America.”

Is Boehner willing to delay the raising of the debt ceiling if he doesn’t get some or all of the items on the House GOP wish list?

When asked this question Thursday Boehner said, “We have $17 trillion worth of debt. This year, the federal government will bring in more revenue than any year in the history of our country, and yet we'll have a nearly $700 billion budget deficit. We have a spending problem that has to be addressed.” He seems to intend to use the debt limit as leverage to get some of the Republican ideas enacted.

At the bottom of the fight over the spending bill is Obamacare or the Affordable Care Act. What’s the public perception of the Affordable Care Act?

Polling by CNBC this week indicated that perceptions depend on what one calls the law.

Accords to the survey, 29 percent support Obamacare compared with 22 percent who support the Affordable Care Act. Forty-six percent oppose Obamacare and 37 percent oppose the ACA. Using the label “Obama” seems to heighten both positive and negative views of the law.