By Kristina Peterson 

WASHINGTON -- A partisan battle of wills over the border wall is set to come to a head this week, with Democrats and President Trump entrenched in an impasse and less than a week left to avoid a partial government shutdown.

With time dwindling before seven spending bills expire at 12:01 a.m. Saturday, lawmakers had little sense of how they would resolve the long-brewing fight over the border wall, which has become a potent political symbol among both parties.

"We're at an impasse and at the moment it doesn't look like things are getting any better," Senate Appropriations Committee Chairman Richard Shelby (R., Ala.) said shortly before the Senate emptied out last week. "There has to be some kind of a breakthrough," he said, before noting, "No movement yet."

The charged political dynamics around funding a wall along the Southern border with Mexico have left both parties with few incentives to compromise. Mr. Trump made building the wall his signature campaign pledge in 2016, and delivering on it has become increasingly important as the 2020 election nears. Mr. Trump had said Mexico would pay for it.

Meanwhile, Democrats, energized by their recent midterm victories, will only gain leverage when they take back control of the House in January. And with dozens of Democrats considering a 2020 presidential run, the party's left wing is in no mood to compromise with the president.

For each party, "the goal of pleasing the base is a huge impediment to getting a deal done," said Greg Valliere, chief global strategist at Horizon Investments. "Trump feels, with some justification, that his base wants a very tough immigration policy and a wall. That's a really enormous promise he made to his base," he said. Meanwhile, Democrats, he said "smell blood. They want to show their base how tough they are."

Republicans winced when Mr. Trump on Tuesday said in a meeting at the White House with House Minority Leader Nancy Pelosi (D., Calif.) and Senate Minority Leader Chuck Schumer (D., N.Y.) that he would be "proud" to shut down the government if Congress won't send him $5 billion to build the wall.

Republicans who had hoped to label any partial shutdown a "Schumer shutdown" backed off that line of attack after Tuesday's meeting. GOP leaders have said they hope to avoid a shuttering of the government.

"A shutdown ultimately is a bad deal from a policy point of view, and it's also detrimental politically," said Sen. Jerry Moran (R., Kan.), a former chairman of Senate Republicans' campaign arm. "There is damage to all of us to Republicans, Democrats, the White House -- whoever's in office -- when this occurs."

But Democrats said Mr. Trump's words saddled him alone with the burden of trying to avoid a shutdown and taking political blame if one occurs.

"The onus is on him -- he's the only one that's talking about a government shutdown," said Sen. Chris Van Hollen (D., Md.), a member of the Senate Appropriations Committee. "It's pretty clear he's going to have to accept responsibility."

GOP leaders had offered to spread the $5 billion in wall funding over two years, which Democrats have rejected. Democrats support border security, but believe the wall is an ineffective use of funds. At the White House on Tuesday, Democratic leaders proposed either passing the six less-controversial spending bills and extending current funding for Homeland Security, which oversees the border wall, through September 2019, or extending current funding for all seven bills. Mr. Schumer and Mrs. Pelosi said Mr. Trump told them he would think about their proposals.

Senate Democrats and Republicans had previously agreed to $1.6 billion in border security as part of their Homeland Security spending bill, but Mr. Schumer said last week that bill couldn't pass the House.

"I want to be crystal clear: There will not be additional appropriations to pay for the border wall," Mr. Schumer said on the Senate floor late last week.

Mrs. Pelosi is under particular pressure to resist agreeing to any funding for the border wall. Although she is expected to win a floor election in January to become the next House speaker, she faces warnings from some House Democrats that they would defect were she to cede too much in negotiations with Mr. Trump.

Both parties are already calculating how the political winds might shift in January if the government does shut down, or passes a very short-term spending patch pushing the fight into next year. Mrs. Pelosi said she would simply pass an extension of current funding in the House, sending it over to the Senate.

"As soon as we took over the Congress, we would pass legislation to open up government and send it to the Senate, and we think it would then go to his desk. But we don't have to go to that place," she said.

But Republicans believe Mrs. Pelosi would rather not have to be still mired in the spending fight when Democrats take control of the House.

If the government does shut down on Saturday, its effects would likely be more limited than previous shutdowns. Congress has already funded swaths of the government, including the Defense and Labor departments. Even for agencies that aren't already funded, employees with essential jobs would still report to work.

"Obviously we want to avoid a government shutdown, but if you look at what the real-world consequences would be, I think this shutdown would be different because we have funded most of the government," said Rep. Richard Hudson (R., N.C.) "I don't think the American people will feel an impact from this like they have in the past."

Still, many federal employees would be required to work without getting paid immediately, though Congress typically votes later to pay them retroactively. More than 420,000 federal employees, including 41,000 law-enforcement officials and up to 88% of the Homeland Security Department staff, would be working without pay, according to estimates from Senate Appropriations Committee Democratic staff. And more than 380,000 federal employees would be furloughed, including big chunks of the Commerce Department, National Park Service and the Forest Service.

--Andrew Duehren and Natalie Andrews contributed to this article.

Write to Kristina Peterson at kristina.peterson@wsj.com

(END) Dow Jones Newswires

December 16, 2018 07:14 ET (12:14 GMT)