With just days to go before the government runs out of money, Republicans on Capitol Hill are rushing to avoid a government shutdown:

WASHINGTON — Republicans are moving toward passing a two-week stopgap measure to avoid a looming government shutdown, but the path in the coming weeks is treacherous, with obstacles on both sides of the aisle as lawmakers push their own priorities, some unrelated to government spending.

With government funding set to expire at the end of Friday, Republicans are aiming to buy more time so they can negotiate over a long-term spending package. The task is complicated by a feud between President Trump and Democrats, whose votes Republicans need to secure passage, and measures on the politically fraught issues of immigration and the Affordable Care Act.

The possibility of a shutdown looms just after Senate Republicans succeeded in passing their sweeping tax overhaul, a moment of triumph for a party that has struggled to produce big achievements despite controlling Congress and the White House. But promises made to secure passage of the tax bill could further complicate negotiations on government funding, and any failure at the fundamental task of keeping the government running would swiftly undercut Republicans’ display of progress.

The threat of a shutdown escalated last week after President Trump fired off a Twitter post attacking the top Democrats in Congress, who in turn pulled out of a planned White House meeting, deepening the rift between the parties at a time when they are already at odds over issues like taxes, health care and immigration.

Republicans’ stopgap spending measure would extend government funding through Dec. 22. On Sunday, the Senate majority leader, Mitch McConnell of Kentucky, tried to play down fears about a coming crisis.

“Look, there’s not going to be a government shutdown,” he said on ABC’s “This Week.” ”It’s just not going to happen.”

But the feud between Mr. Trump and the top Democratic congressional leaders provided ample cause for concern. The acrimony is a stark change from just a few months ago, when Mr. Trump sided with those leaders, Senator Chuck Schumer of New York and Representative Nancy Pelosi of California, on a short-term deal to fund the government and increase the debt limit.

Now, the president is in direct conflict with “Chuck and Nancy,” as he has called them, at a time when Democrats have substantial leverage. Democrats can block the stopgap spending measure in the Senate, and Democratic votes could also be needed to get the measure through the House if enough Republicans rebel against it. Any long-term spending package would also need Democratic votes.

Citing the power that Democrats hold under Senate rules, Representative Trent Franks, Republican of Arizona, complained last week that his party was being forced, despite having majorities in both houses, to “produce basically a Democrat document.”

“It’s an untenable, unworkable thing, and it’s a hell of a way to run a railroad,” he said.

The stopgap spending measure would provide more time for negotiations between the two parties over raising strict spending caps that were imposed in 2011 as they try to work toward a long-term spending deal for the 2018 fiscal year, which began Oct. 1.

“We want to keep government open,” Ms. Pelosi said last week. “That’s what we are about.” But she emphasized the need to provide an acceptable increase in nondefense spending as part of a deal to raise the spending caps, citing issues like providing funding to address the opioid epidemic.

Lawmakers are also pushing to provide tens of billions of dollars in additional disaster relief in response to Hurricanes Harvey, Irma and Maria. Members of both parties called a request from the White House last month to provide $44 billion in aid insufficient.

Complicating matters further are divisive issues being dealt with on Capitol Hill beyond financing the government. Republicans are closing in on sending their tax overhaul to Mr. Trump, a feat that would represent their first major legislative accomplishment of his presidency, and they hope to finish that work by Christmas.

In addition to spending limits and questions regarding the size of relief packages that hit Florida, Texas, and Puerto Rico over the summer and early fall, there are several other issues that could complicate negotiations both over the coming days and between now and December 22nd even if Republicans are able to punt the ball that far down the road. One of these, of course, is the tax bill that has passed the House and Senate but remains to be negotiated over by a House-Senate conference committee that would need to come up with a bill that can pass both bodies without any changes before anything can get to the President’s desk. While the odds are fairly high that this will succeed given the fact that Republicans are eager to be able to score a major legislative victory before the end of the President’s first calendar year in office, there remain several unresolved issues regarding the bill that could prove problematic. Chief among those include the fact that the House and Senate versions of tax reform differ in the way in which they would change the rates at which individual income taxes are calculated and the number of brackets that would exist at the end of the day. There are also differences with regard to the treatment of popular deductions such as the mortgage interest deduction and the deduction for state and local taxes, including property taxes. Finally, of course, there’s the fact that the Senate version of the bill would eliminate the individual mandate in the Affordable Care Act, a move that the Congressional Budget Office estimates would result in at least 13 million Americans being knocked off the health insurance rolls.

In addition to tax reform, other issues could complicate efforts to reach an agreement on a final spending bill. Chief among these is the fate of the Deferred Action For Childhood Arrivals program established by the Obama Administration. In September, President Trump announced that the program, popularly known as DACA, would come to an end in March 2018. Subsequent to that announcement, though, the President allegedly reached an agreement of some kind with House Minority Leader Nancy Pelosi and Senate Minority Leader Chuck Schumer to save the program in some form via legislation and several Republicans in the House and Senate endorsed the idea of a legislative fix for DACA that would allow the people who have benefited from the program since it was announced to remain in the country and, eventually, obtain legal status and citizenship after proper periods of time have passed. So far, though, no legislative action has been undertaken with regard to the program and, with time ticking down for current and future DACA beneficiaries, Democrats have been threatening to withhold support for any final spending bill that doesn’t include some kind of provision addressing the DACA issue.

In the end, it seems likely that Congress will at least be able to avoid a shutdown by getting a temporary spending bill passed by the end of the week. The only thing that will accomplish, though, is to kick the can down the road two weeks to December 22nd, just before Congress is set to depart for the Christmas holidays. This means that all of the conflicts standing between legislators and a budget deal will still be there and still be unresolved. Whether or not a deal can be reached is something only time will tell.