Sen. Kamala Harris (D-Calif.) walks from the Senate floor between votes on procedural measures leading up to potential tax overhaul legislation on Dec.r 1, 2017. (Jonathan Ernst/Reuters)

This was supposed to be the week that Democrats vowed to assert maximum leverage over talks to keep the federal government open — but they may not be in sync about what they’re fighting for.

Liberals from urban districts and coastal states are vowing to withhold support for a must-pass spending bill if Republicans don’t resolve the legal status of young immigrants. Moderates facing reelection in states President Trump won last year are more focused on boosting funding for children’s health programs, government-backed pensions and programs to combat opioid abuse.

The conflict resurfaces a mathematical reality of Trump’s Washington: Republicans control Congress and the White House but need Democrats to keep the government operating. But with different midterm election priorities in the House and Senate, Democrats are struggling to fight Republicans on a united front.

Ever since Republicans retook control of the House in 2011 and the Senate in 2015, party leaders have leaned on at least a few dozen Democrats to help pass spending bills in the face of opposition from dozens of fiscal conservatives. Once again this week, roughly three dozen ardent conservatives in the House are balking at the latest GOP spending plan, raising concerns that the government will miss a late-Friday spending deadline.

To avoid a shutdown, House Speaker Paul D. Ryan (R-Wis.) is moving ahead with plans this week to pass a two-week extension to Dec. 22, probably forcing action on a broader spending plan just before the Christmas holiday.

If Congress doesn't pass a spending bill, the costly consequence would be a government shutdown. Here's a look at what happens when the government is not running. (Joyce Koh/The Washington Post)

If Republicans need Democratic votes, “we’ve made very clear the kinds of things that we think are urgent and necessary to address as part of this,” Rep. David N. Cicilline (D-R.I.) said.

Democrats this week released a laundry list of unfinished business they expect to be addressed: new funding to combat opioid addiction, shore up government-backed pension plans and pay for major infrastructure projects; a new law to reauthorize the Children’s Health Insurance Program and cash-strapped community health centers; more money for states ravaged by recent hurricanes and wildfires; and a permanent solution for “dreamers,” the 1.5 million children of undocumented immigrants at risk of deportation.

In September, House Minority Leader Nancy Pelosi (D-Calif.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) agreed with Trump to extend spending levels through this Friday — disregarding a push by Ryan and Senate Majority Leader Mitch McConnell (R-Ky.) to extend spending levels until after next year’s elections.

Democrats touted the bipartisan agreement as an opportunity to build support for their top priorities. Under criticism from some in her party, Pelosi defended her work with Trump.

“I make no apology for doing that with the person who is going to sign the bill,” she said in an interview in September. “It gives you great leverage.”

But conversations with rank-and-file Democrats exposed wide differences over how to wield their clout.

“We have to address the Dream Act,” said Rep. Pramila Jayapal (D-Wash.), a first-term lawmaker seen as a rising star in her party.

President Trump speaks to reporters on the White House South Lawn on Monday. (Susan Walsh/AP)

“Any bill that funds the government must also include a fix for DACA,” Sen. Kamala D. Harris (D-Calif.) said in a Senate floor speech.

“Obviously, CHIP,” said Sen. Claire McCaskill (D-Mo.), who is running for reelection in a state Trump won by more than 18 points.

“CHIP and DACA are the two I really want to try to get resolved,” said Sen. Tim Kaine (D-Va.).

At a news conference with Schumer on Tuesday, Sens. Sherrod Brown (D-Ohio) and Tammy Baldwin (D-Wis.), who are also seeking reelection in states Trump won, touted the need to shore up underfunded pensions or provide money for infrastructure projects. Neither mentioned immigration or voting against a temporary spending bill.

The Dream Act would provide permanent legal protections to about 690,000 dreamers and allow them to eventually apply for U.S. citizenship. It is backed by members of both parties in the House and Senate.

The legislation has become a rallying cry for many progressives and dozens of House Democrats, including of the congressional Asian, black and Hispanic caucuses. At least six Democratic senators — five of whom are potential 2020 presidential candidates — have said they would vote against any spending bill if Congress fails to protect dreamers.

If Republicans “don’t have the votes and they need Democratic votes, then they cannot expect that we will vote for a bill that does not include our priorities,” Jayapal said.

CHIP provides health-care services for 9 million children and 370,000 pregnant women. Funding began drying up Sept. 30, and while many states have enough money to keep their individual programs afloat for at least a few months, five could run out in late December.

“We’ve got clinics all across the United States that are going to have to start turning children away because CHIP has not been funded,” warned Rep. Zoe Lofgren (D-Calif.). “That has to be in this bill. We can’t allow those children who have medical needs to be turned away.”

But that’s a step too far for moderates like McCaskill, Kaine and Rep. Matthew Cartwright (D-Pa.), who represents a rural district Trump won by double digits.

The last time the government shut down, in 2013, “I was one of the loudest voices talking about how dumb an idea that is to shut down the government — and how expensive it is,” Cartwright said.

Asked whether his opinion on the issue would be different if Hillary Clinton had won his traditionally Democratic district, Cartwright flashed a tight smile.

“Only in extremis would I vote to shut down the government,” he said.

Asked about the spending bill, Sen. Joe Manchin III (D-W.Va.) pulled a double-length index card out of his breast pocket with details of his most pressing concerns: final passage of an Internet taxation bill; a bill to bolster federal funding to combat the opioid crisis; another bill to buoy a federal pension program for coal miners; and more money for CHIP, an issue he called “very concerning to me and the people of West Virginia.”

Pressed about his stance on immigration, Manchin cut off a reporter.

“You’re talking about DACA and dreamers? Yeah, that’s very, very important, and I really sympathize with them, but I’ve told them that I’m not a vote to shut down,” he said before walking away.

Schumer, whose job it is to protect 25 Democratic Senate seats in next year’s elections, said he didn’t think Democrats would have to vote against a spending bill — predicting that a bipartisan plan to protect dreamers would soon be reached.

Senior aides to top Democratic leaders and Trump met again Tuesday to sort out details of the spending agreement, according to multiple aides familiar with the talks. A final White House meeting between Trump and top leaders isn’t scheduled until Thursday, leaving little time to reach a spending agreement.

The fate of the plan rests with House Republicans, who remained unsettled Tuesday about how to proceed.

Ryan met with leaders of GOP factions Tuesday afternoon, but they failed to reach a consensus. While most House Republicans are okay with a two-week extension, members of the conservative Freedom Caucus — wary that Democratic priorities could get wrapped into a last-minute deal — want a later deadline.

Emerging from a closed-door meeting Tuesday morning, Rep. Kay Granger (R-Tex.), the powerful chairwoman of an appropriations subcommittee on defense, laughed when asked whether there was any clarity on the timing of a new spending bill.

“There’s no clarity,” she said.

Rep. Mark Amodei (R-Nev.) expressed disgust with the entire process and said Democrats should be happy because Republicans clearly do not have a majority of the votes needed to proceed on their own.

“Right now, if I were them, I’d be happy,” Amodei said of Democrats.

Josh Dawsey and Erica Werner contributed to this article.