Competing interests in both chambers ahead of government shutdown deadline

Washington(CNN) After this week's tax vote, the spotlight will shift to a vote on a spending bill to avoid a government shutdown by midnight Friday.

Republicans have repeatedly said there will be no shutdown, but they're not able to say how they will definitively avoid one with a number of competing interests at stake in both chambers.

There's chatter of potentially kicking the can down the road again and passing a short-term continuing resolution that lasts until January, so that members have more times to discuss rather than jam a bill in just before Christmas.

Regardless, aides have said they don't expect Congress to leave town until Friday.

Among the complications:

• Republicans will need at least some Democratic votes in order to pass the spending bill.
• Republicans want more in defense spending, while Democrats want more in domestic spending.
• Democrats also want some kind of deal on how to handle the expiration of the Deferred Action for Childhood Arrivals (DACA) program -- which is a hard sell for conservatives.
• Republican Sen. Susan Collins of Maine has been getting promises on stabilizing Obamacare insurance markets (in exchange for a yes vote on tax reform), but that's a no-go for House Freedom Caucus members.

As CNN's Lauren Fox and Deirdre Walsh reported last week, multiple Republican members have said that there is so much frustration about the Senate that some members were urging the House to just pass their bill and skip town, forcing the Senate to decide between shutting down the government or passing the House version of the bill.

CNN's Tal Kopan reported on Thursday that the current plan, according to multiple lawmakers and aides, is for the House to pass a bill that would fund defense for a year, reauthorize children's health insurance, and punt the rest into January. That bill is dead on arrival in the Senate, where 44 Democrats have gone on record opposing it.

The belief is that the Senate will send something back to the House, likely with Obamacare payments or possibly just a short-term funding extension into January. All the while, parties negotiating a DACA deal in both chambers remain optimistic about the progress of talks.

The House vote could be difficult, however. Obamacare payments will be tough to swallow for conservatives. And defense hawks concerned about continued temporary funding of the military may not be willing to go along with a short-term fix.

One other complication: FISA authorization for surveillance expires at the end of 2017 and there is no clear plan yet to extend it. Few, if any lawmakers, want it to expire, but there are three different reform proposals that have advanced through committee between the House and Senate and no one really has had time to debate which version should move forward. Plus, the administration has expressed support for a clear extension with no reform.

Three Republicans leaving last week' House GOP meeting all mentioned it as one of the biggest sticking points, suggesting lawmakers could pass a short-term extension to try to buy themselves time to have a legitimate debate about government surveillance out of the drama of year-end spending.