Washington (CNN) President Donald Trump's expected decision to end DACA, but leave some time to save it, punts the popular program that protects young undocumented immigrants to Congress -- but passage of a legislative solution remains a steep uphill climb.

Trump is expected to announce Tuesday that he will end the Obama-era Deferred Action for Childhood Arrivals program, but will offer a six-month delay to give Congress time to come up with a fix, according to sources familiar. Those sources have cautioned that this was the President's thinking as of Sunday night and could shift ahead of his scheduled Tuesday announcement.

Such a plan would put the issue on Congress' shoulders amid a busy fall, squeezing Republican and Democratic leadership to decide what their bases could swallow to find a compromise that would keep the nearly 800,000 people who benefit from the program from having their lives upended.

As the administration has held meetings for weeks about how to respond to an ultimatum from 10 state attorneys general about the future of DACA, members of Congress have publicly and privately called on the administration to preserve the program long enough for a legislative fix.

But President Barack Obama announced the executive action -- which protects undocumented immigrants brought to the US as children from deportation and allows them the ability to work and study -- as a response to years of congressional inaction. Now, they will have to take ownership of averting an end to the popular program that has the widespread support of Democrats, moderate Republicans and the business and education communities.

"Now the hot potato's back in their lap," said one senior lobbyist, who spoke on condition of anonymity to be candid. "Some Republicans would welcome the opportunity to show they're pro-Latino and do something on this, but on the other hand some would be just as happy to say 'hell no, we're not doing this because it's amnesty.' And so we've got (House Speaker Paul) Ryan in the hot seat figuring out where's his base and where does he go."

Ryan on Friday told a Wisconsin radio station that he wants Trump to keep DACA in place so Congress can work on a legislative solution. While he did not support Obama's creation of the program, he has been sympathetic to the so-called Dreamers benefited by it and said he has been having conversations about figuring out a path forward for them.

His office and the other leadership offices in Congress were all quiet on Monday, holding off comment until the President makes a formal announcement.

A Democratic leadership aide in the Senate said that working with Republicans on a fix "will be a high priority" for Democrats if Trump announces DACA's end on Tuesday, but conversations will happen about next steps when members return from August recess that day.

A tough path to compromise

There has been a steady stream of Republicans supporting a legislative version of DACA since Friday and Ryan's comments, including Utah Sen. Orrin Hatch and Arizona Sen. Jeff Flake.

Republicans have to balance roughly two-thirds of their membership for whom anything supporting undocumented immigrants is a tough vote with the rest, who could potentially benefit politically from such a vote.

House Rules Committee Chairman Pete Sessions, a Texas Republican, said Monday on CNN's "New Day" that he could support a guest worker program for the population, calling it "more than half a loaf" and "the minimum" toward helping Dreamers.

"I think if we do it creatively and smart, we would even have the votes for that," Sessions said.

"The legislative and executive branch should put aside passivity and partisanship and finally modernize our immigration laws," Oklahoma Sen. James Lankford said in a statement. "It is right for there to be consequences for those who intentionally entered this country illegally. However, we as Americans do not hold children legally accountable for the actions of their parents."

Arkansas Sen. Tom Cotton, an immigration hawk who has written legislation that would cut legal immigration, told the Washington Examiner that he could support a fix for Dreamers if paired with his legislation and other conservative wish list items. But that approach doesn't even have enough votes among Republicans, and would be a nonstarter as an option.

Eighteen Republicans have co-sponsored a bill from Florida Rep. Carlos Curbelo that would make a version of DACA permanent, and North Carolina Sen. Thom Tillis is planning to introduce a version of that bill in the Senate when Congress returns. Lawmakers believe more Republicans would vote for the proposal if it came to the floor.

Democrats

Democrats almost universally support protecting Dreamers and have long called for a solution. But the devil is in the details -- and it remains unclear to insiders of the debate whether both sides can swallow enough of a compromise to reach a solution.

They have been adamant that they will not accept any deal to fund even small amounts of a border wall or increased immigration enforcement, and cuts to legal immigration would be unacceptable.

"Already you've seen the fracturing with people saying you need to pass this as part of border security, or other people saying you need to pass this with cuts in legal immigration, and another group saying you need to pass this on its own, and already that lack of consensus makes this unfeasible in Congress," said Leon Fresco, an immigration attorney, former Obama administration immigration official and former aide to Senate Minority Leader Chuck Schumer.

Fresco also pointed to advocacy groups on the left as key to Democrats' decision-making. As long as those groups insist, as they do, that they won't accept a DACA fix in exchange for more enforcement, Democrats are stuck.

"The politicians are being bolstered by the groups, and the groups themselves are saying don't trade any enforcement for DACA," Fresco said. "If that were to change, then the fundamental dynamics of the issue would change, but at the moment that's not where the advocacy community is -- they want a fight on DACA to show that the President is on the wrong side of these issues."

Another lobbyist familiar with the issue acknowledged that even supporters of DACA begrudgingly recognize that it will likely take Trump ending DACA to incentivize Congress to act -- and it could change Democrats' calculus.

"DACA has to go away for that to become a possibility," the lobbyist said. "If groups on the far left are smart, they'll take (the wall). ...That seems to me like a win-win for everybody, but right now there's no pressure on Schumer to do anything, and if the groups don't press him, then it won't happen. So I think it's up to them."