President Trump is set to huddle with congressional leaders on Tuesday as lawmakers scramble to strike a spending deal that will prevent the government from shutting down when its funding dries up next month.

White House officials want to avoid a showdown over immigration that could upend spending negotiations by injecting a contested partisan issue into the conversation. Republicans, too, have signaled an unwillingness to allow the government to shut down at the height of their push to pass a tax reform bill, which they hope to place on the president’s desk before the end of the year.

Some Democrats, however, have shown interest in pursuing an immigration deal tied to a bill that funds the government through the end of the next fiscal year. Others have even suggested the immigration deal must be tied to the short-term funding bill lawmakers expect to pass in order to buy more time to negotiate the larger spending package.

“In the past, [Senate Minority Leader] Chuck Schumer has repeatedly made clear that he opposes government spending bills with strings attached. We hope Democrats follow Sen. Schumer’s lead and not hold government funding hostage to their own pet legislative projects, which would jeopardize our national security,” Hogan Gidley, White House deputy press secretary, told the Washington Examiner.

“Government spending bills should fully fund our military, homeland security, and all essential operations to protect the American people’s prosperity and safety,” Gidley added.

When Trump sits down with House Speaker Paul Ryan, R-Wis.; House Minority Leader Nancy Pelosi, D-Calif.; Senate Majority Leader Mitch McConnell, R-Ky; and Schumer, D-N.Y., for a meeting at the White House Tuesday afternoon, the so-called “Big Four” will have a packed agenda to discuss.

Trump’s previous closed-door conversations with Pelosi and Schumer yielded the framework of an immigration deal that conservative critics said would amount to amnesty for hundreds of thousands of undocumented immigrants, as well as the continuing resolution that set Congress up for a holiday season full of spending talks. His friendliness with the Democratic leaders, to whom he referred as “Chuck” and “Nancy,” revived skepticism among some Republicans and rocked his relationships within the GOP conference.

Lawmakers from both parties remain split on a range of issues central to the spending fight, including defense appropriations and funding for disaster relief after a spate of hurricanes hit Puerto Rico and Southern states this summer.

Complicating a process that already has the potential to get messy is a Democratic push to include the immigration issue in the spending bill. Some Democratic lawmakers have even threatened to oppose any funding mechanism that fails to address the Deferred Action for Childhood Arrivals, or DACA, program, an Obama-era initiative that extended protections to undocumented immigrants who were brought into the U.S. as children.

Trump announced in September that he plans to wind down DACA by March, giving Congress six months to craft legislation that would preserve temporary legal status for the roughly 800,000 people eligible for the program. However, nearly three months into that window, lawmakers remain at odds over how and when to strike a DACA deal that can attract bipartisan support.

Sen. Lindsey Graham, R-S.C., has advocated for attaching DACA legislation to the spending bill Congress must pass next month.

And a handful of liberal lawmakers — including Sens. Bernie Sanders, I-Vt.; Cory Booker, D-N.J.; and Kamala Harris, D-Calif. — have suggested they will vote against spending legislation that does not codify DACA protections.

Democratic congressional leaders have not signaled whether they will insist on folding a DACA fix into the spending bill.

But most GOP members favor saving the immigration battle for another day given the urgency of other big-ticket items on their agenda in December, such as tax reform and legislation to fund the government through September.

Republican congressional leaders have indicated they want to keep DACA discussions out of the year-end spending mix and focus solely on appropriations as the Dec. 8 deadline to avert a shutdown approaches. White House officials also hope to see Congress leave the thorny issue out of spending talks.

A senior GOP aide told the Washington Examiner that negotiations could also stall over defense spending caps.

Raising those limits on funding for the military has emerged as a priority for Republicans, but Democrats have avoided meeting with their counterparts in the majority on the issue, the aide said.

The lingering debate over defense caps is one reason lawmakers expect to rely on the short-term spending bill to keep the government open when the current continuing resolution expires in less than two weeks.

A Senate Democratic aide said Democrats see a “bipartisan path” on defense spending caps and other sticking points in the legislative debates facing Congress next month.

“In three and a half weeks, the Republican Congress has to figure out a way to reach a caps deal with parity between defense and non-defense, write an omnibus, extend funding for community health centers, reauthorize [Children's Health Insurance Program], fund disaster recovery, and pass the [Development, Relief, and Education for Alien Minors] Act,” the Democratic aide told the Washington Examiner. “There is a bipartisan path to getting there, and we hope that we can make progress on all of those issues.”

Whether Democratic leaders back calls from their party’s progressive wing to fight for a DACA deal in the omnibus could determine whether Republicans face the prospect of a shutdown on their watch. GOP aides in Congress and the administration maintain, however, that blame for a hypothetical shutdown over immigration would fall squarely on Democrats if they chose to wage that battle now. Republicans do not appear interested in pursuing funding for Trump’s promised border wall at this juncture, citing their focus on tax reform.

Democratic leaders could find a DACA deal difficult to sell with so little time left on the congressional calendar.

Schumer has even blasted the concept of playing brinkmanship over immigration reform in the past.

In 2013, Schumer said Democrats would create “governmental chaos” if they shut down the government over their desire to pass immigration reform.