Some House Democrats are raising the specter of withholding support for must-pass spending legislation later this year in response to President Trump's hard-line immigration proposals — meaning the fate of roughly 690,000 younger undocumented immigrants could become a major factor in negotiations to keep the government open after December.

Democrats on Monday dismissed Trump's calls to construct a wall along the entire length of the U.S.-Mexico border, crack down on "sanctuary cities" and seek ways to curb Central American migrants from illegally crossing into the country. But conservative Republicans insisted that such issues must be addressed before Congress considers offering legal status to immigrants brought to the country illegally as children, a group known as "dreamers."

The prospective standoff is the latest hurdle in the years-long struggle on Capitol Hill to reach an accord on reforming the nation's immigration policy. The administration's lengthy list of demands dampened growing optimism among lawmakers from both parties that they could strike a deal to protect recipients of Deferred Action for Childhood Arrivals (DACA), the Obama-era work program for "dreamers" that Trump announced last month he would terminate.

"What the White House put forward is a complete non-starter," House Minority Leader Nancy Pelosi (D-Calif.) said in an interview, blaming Trump's senior policy aides for advancing "un-American" ideas on how to deal with immigration.

"There's nothing in it to negotiate because it does not have shared values of who we are as Americans," she added.

Facing a tight deadline — work permits for DACA recipients will begin expiring in March — Pelosi said her conference remains unified in opposition to Trump's ideas. But comments from Democrats Monday showed they do not have consensus on how to respond.

Some members of the Congressional Hispanic Caucus signaled they would consider withholding support for must-pass spending bills in December unless the DACA recipients are granted legal status with a path to citizenship. In recent years, near-unanimous support from Democrats has been needed to pass government spending bills and legislation to raise the government's borrowing limit amid opposition from dozens of fiscal conservatives who are against increased spending without subsequent budget cuts.

Rep. Luis Gutierrez (D-Ill.) called the spending bill debate a defining moment for Democrats.

"I'm not saying we should shut down the government, but if you want a budget with Democratic votes, then it's got to have some Democratic priorities," he said.

Rep. Michelle Lujan Grisham (D-N.M.), who chairs the Hispanic Caucus, said withholding votes for spending legislation "is definitely on the table," but she added that Democrats will continue to try to build consensus with moderate Republicans on an immigration plan.

Immediately threatening to vote against spending legislation "doesn't open the door for moderate Republicans" who support immigration reform bills, she told reporters.

Pelosi also cautioned it was too early for such threats, and she noted that Republicans, who control both chambers of Congress, could pass a spending bill on their own if necessary.

"I fully intend to use every possibility, but we're not at that place yet," she added. "Right now, we're trying to get Republicans to vote on what we believe."

Democrats were not the only ones trying to figure out their next move. GOP leaders also were deliberating over how to proceed, fretting the White House's hard-line position would complicate talks and reduce the chances for a relatively quick deal — which Trump has said he wants.

"It's safe to say that many Hill Republicans do not think the WH immigration principles were helpful," one senior House GOP aide said in an email. "The principles are clearly non-starters with Democrats and divide Republicans."

This aide, who was not authorized to speak on the record about ongoing deliberations, emphasized that GOP leaders "didn't overreact" last month when Trump met with Pelosi and Senate Minority Leader Charles E. Schumer (D-N.Y.) to discuss a path forward on DACA, alarming Republicans that the president would cut a deal without them.

"And we're not going to overreact when his staff releases some principles," the aide said. "We're focused on finding a solution."

In a statement, House Speaker Paul D. Ryan (R-Wis.) said his members "will review these principles and continue to consult with our conference and the administration to find a solution."

Last month, Ryan convened a cross-section of his caucus to explore immigration policy options — a group that includes House Majority Leader Kevin McCarthy (R-Calif.), a proponent of constructing a border wall, House Judiciary Committee Chairman Robert Goodlatte (R-Va.), an immigration hawk, as well as moderates from immigrant-saturated districts, including reps. Carlos Curbelo (R-Fla.) and Mario Diaz-Balart (R-Fla.).

Senators, who are on a week-long Columbus Day recess, remained mostly silent about Trump's ideas on Monday. Senior Republican aides said any consensus on how to proceed won't come together until the Senate reconvenes after members return next week.

Sens. David Perdue (R-Ga.) and Tom Cotton (R-Ark.) have proposed legislation to slash legal immigration in half over the coming decade, a concept that was included in the Trump administration's principles on Sunday. White House aides said the curbs would help offset the potential legalization of the "dreamers," a population estimated at more than 1.5 million.

"The immigration priorities President Trump has outlined are spot on," Perdue said in a statement.

Advocates on both sides of the debate said they did not interpret the administration's principles, which also include the hiring of 10,000 additional immigration agents, as nonnegotiable but as an opening bid.

"The White House is willing to negotiate. Democrats are not," said Mark Krikorian, executive director of the Center for Immigration Studies, which advocates for lower immigration levels. "That means the odds of no bill by March have increased — not because the White House principles are overly ambitious but because Schumer is not going to make a meaningful counter offer. They want amnesty in exchange for nothing."

But Ali Noorani, executive director for the National Immigration Forum, said he believes there remains a significant majority on Capitol Hill interested in forging a deal no matter where the White House stands. If they fail, he added, it will be Trump who takes most of the blame for choosing to end the DACA program, which has broad public support.

"If that's the case, Trump will have snatched defeat from the jaws of victory in a pretty impressive way," Noorani said.

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