Lawmakers and advocates on both sides began to stake out positions Monday for an extended public fight over whether Congress should provide legal status to young undocumented immigrants known as "dreamers" as President Trump is preparing to rescind Obama-era protections for them.

Moderate congressional Republicans, and even some conservatives, suggested that they are open to crafting a legislative deal that could offer permanent legal status to hundreds of thousands of immigrants who have been in the country illegally since they were children. Democrats lambasted Trump for his expected decision and called on the GOP to join them to protect the dreamers.

Urgency on Capitol Hill has mounted amid reports that Trump will end the Deferred Action for Childhood Arrivals program, which has allowed nearly 800,000 people to live and work in the United States without fear of deportation. The Trump administration, which is scheduled to announce the decision Tuesday, is leaning toward terminating the program but delaying enforcement for six months to give lawmakers time to find a solution, according to people briefed on the White House's deliberations.

"Congress, get ready to do your job - DACA!" Trump wrote early Tuesday in a tweet, further signaling apparent plans to kick the hot-button issue back to lawmakers.

Trump faces a Tuesday deadline from Texas and several other states that have vowed to sue the administration over DACA if the president does not terminate it. Attorney General Jeff Sessions, an immigration hawk, has suggested that the Justice Department would not be able to defend the program's constitutionality in court and has lobbied Trump to end it. Other top advisers, including Chief of Staff John F. Kelly, have pushed him to maintain the program until lawmakers act.

Yet the odds that a sharply polarized Congress could strike a deal — steep in the best of times — are considered especially difficult at a time when lawmakers face a busy fall agenda. Congress is under pressure to raise the federal debt limit, pass a spending bill and approve a defense authorization bill, at a time when Republicans also hope to consider a tax plan and potentially try once again to repeal the Affordable Care Act.

Sen. Lindsey O. Graham (R-S.C.), who has been involved in previous bipartisan immigration reform efforts, said he would support Trump's plan to end DACA after a six-month delay. In a statement, Graham said the program amounted to "presidential overreach" by President Barack Obama, who created it by executive action in 2012.

But Graham added that he empathizes with the dreamers who "know no country other than America. If President Trump makes this decision, we will work to find a legislative solution to their dilemma."

House Minority Leader Nancy Pelosi (D-Calif.) said Trump is poised to "break the hearts and offend the morals of all who believe in justice and human dignity." She called on Republicans to pursue legislation to protect dreamers "from the senseless cruelty of deportation and shield families from separation and heartbreak."

Trump's decision to include a six-month delay could be a bid to shift some of the political pressure and consequences over the dreamers onto congressional Republicans. House Speaker Paul D. Ryan (Wis.), Sen. Orrin G. Hatch (Utah) and several other GOP leaders have urged Trump not to end the program and to let Congress pursue its own course of action.

The president and his senior advisers continued to deliberate Monday afternoon, and aides cautioned that Trump could still change his mind ahead of the announcement. Important details such as whether the administration would continue to accept DACA applications and issue renewals for two-year work permits during the six-month delay remained unresolved.

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It also remains unclear whether Texas and the other states would move forward with their lawsuit if Trump announces that he will end the program in six months.

A deal on the dreamers has eluded Congress before — most recently in 2010, when the Dream Act, which would have offered the younger immigrants a path to citizenship, failed by five votes in the Senate after passing the House.

Ryan and other GOP leaders have not laid out a new legislative path, including whether the dreamers' future would be addressed in isolation — which would appeal to Democrats and moderates — or be coupled with proposals to increase border security and tighten immigration controls, which could win greater support from conservatives.

Sen. Tom Cotton (R-Ark.), an immigration hard-liner, suggested that he would be open to giving the dreamers legal permanent residence provided that any deal also include his legislative proposal, called the Raise Act, which would slash legal immigration levels by half over a decade.

Trump offered public support for that bill during an appearance with Cotton and Sen. David Perdue (R-Ga.), its co-sponsor, at the White House last month.

In an interview with the Washington Examiner, Cotton emphasized that he thinks the new class of green-card holders represented by the dreamers must be offset with cuts elsewhere.

"We should find a way to give [them] legal status," he said, "but we also have to mitigate the inevitable consequences of that action."

Others have suggested that Trump could attempt to use the dreamers to bargain for a down payment — an estimated $1.6 billion — on the U.S.-Mexico border wall he promised voters during the campaign. Senior lawmakers have shown no signs that they plan to support the wall in upcoming budget negotiations.

Such package deals were quickly discounted by immigration hawks and immigrant rights advocates Monday.

"Why would you have to make a bargain with the rule of law?" asked Rep. Steve King (R-Iowa), an early Trump supporter who has vehemently opposed legal status for undocumented immigrants. "These are bright lines we're talking about."

Frank Sharry, executive director of America's Voice, an immigrant rights organization, said that advocates are still pressing the White House to maintain DACA and that they hold out hope that Trump will protect the program.

However, if the president moves to unwind it, Sharry said, advocates think they will have the upper hand in a legislative fight, given polls that show broad public support for allowing dreamers to stay in the country.

A trade of the dreamers for tougher immigration restrictions or border wall funding "would not even pass the laugh test," Sharry said. "The momentum is with the dreamers."

Meanwhile, leading Democrats have said privately that they think Trump has been boxed in politically. His inability to secure funding for the border wall is wearing down support among his base, these Democrats said, while his hard-line immigration rhetoric is hurting him with moderates.

When rumors about Trump's expected actions on DACA first surfaced nearly two weeks ago, Senate Minority Leader Charles E. Schumer (D-N.Y.) tweeted that dreamers "are not a bargaining chip for the border wall" funding or to pay for an "inhumane deportation force."

One factor that could alter the political calculus for Democrats is if the Trump administration were to start deporting large numbers of immigrants whose DACA protections have expired. Although administration officials have said they are not targeting dreamers, immigration rights advocates said they fear that more dreamers are bound to be swept up in deportation proceedings as the Department of Homeland Security widens its enforcement net.

Leon Fresco, an immigration lawyer who previously served as an aide to Schumer, said he doesn't think Congress would muster the political will to reach a deal on the dreamers — even if the administration begins ramping up deportations.

"I don't know if that's a strategy Democrats will want to reward or not. I don't know where the advocacy community will be," Fresco said. "Really, I just see a lot of bluster but nothing happening."

Immigration hawks, meanwhile, are gearing up to ensure that Ryan and other congressional moderates do not "give away" the dreamers without getting enough in return. Mark Krikorian, executive director of the Center for Immigration Studies, which advocates for lower immigration levels, has proposed a deal that couples legal status for dreamers with the immigration curbs in the Cotton-Perdue bill.

What he does not support, Krikorian emphasized, is legalizing the dreamers for money for the border wall.

The "appeal of the six-month delay" in rescinding DACA is that "it kicks it beyond the budget fight," Krikorian said.

To Trump supporters outside Washington, the most important part of the president's decision is living up to his campaign promises, said Dale Jackson, a conservative radio host in Huntsville, Ala.

Jackson, who in February asked then-White House press secretary Sean Spicer why Trump had not ended DACA, said he does not expect Congress to close a deal to provide a haven for dreamers. Trump, he suggested, knows that, too.

"Trump is probably doing the best he can do in this situation," Jackson said. "He ends the program and asks Congress to come up with a solution knowing . . . they can't. You see guys like Paul Ryan saying they want to do something to protect these people but they are not able to get anything through Congress."

Ed O'Keefe, Maria Sacchetti, Sean Sullivan and David Weigel contributed to this report.