Washington (CNN) The fate of hundreds of thousands of DACA recipients could rest with moderate lawmakers in the Senate -- and whether they can convince President Donald Trump that their path forward is the only answer left, even if it doesn't give him everything he wants.

A group of bipartisan senators led by Republican Sen. Susan Collins of Maine announced Wednesday that after weeks of meetings, they finally had a proposal that would protect 1.8 million individuals eligible for the Deferred Action for Childhood Arrivals program in exchange for $25 billion in border security.

But the plan stops short of President Donald Trump's demands, including an end to the diversity visa lottery and an overhaul of legal immigration.

The proposal quickly faced resistance from virtually all corners of Washington. Sixty votes will be needed to get the plan through the Senate.

Democrats aren't united behind it, with some liberals worrying it doesn't go far enough to protect undocumented immigrants. Republicans are looking at what it doesn't contain and watching for the White House's response, after it forcefully has criticized other moderate immigration proposals this month.

"We're not going to win every game, but the fact that the team has taken to the field on a bipartisan basis is encouraging," said Sen. Dick Durbin of Illinois, the Democratic whip.

As the clock ticked into Wednesday evening, the quest for 60 votes intensified. Leaders of the bipartisan group circulated their proposal, making the pitch to those in their respective parties that it could be the only option left before Majority Leader Mitch McConnell pulls the plug on what he has said will be only a weeklong debate.

Other bipartisan proposals also emerged, including one from Colorado's Sens. Michael Bennet, a Democrat, and Cory Gardner, a Republican, leaving questions about whether it was fair to prioritize one bipartisan proposal above another.

Meanwhile, the timeline didn't seem to force wavering Republican moderates to commit to whether they would back a bipartisan deal.

Senators and aides involved in the process described a mix of brief optimism countered by some confusion and overarching concern that the moment to finally tackle immigration was growing more likely to slip by the Senate.

"It goes back and forth," one Democratic senator told CNN. "One moment it feels like we're almost there and everyone's really gonna hold hands and jump together. The next it feels like everything is about to fall apart."

"The latter," the senator acknowledged, "has prevailed in my mind more times than the former today."

Sen. Chris Coons, a Democrat from Delaware, said he'd counted nine Republican supporters for the bill.

"I'm very optimistic that this tough bipartisan compromise will get 60 votes," Coons said.

Shrinking middle

The latest test for moderates on immigration comes when the Senate has an incredibly shrinking middle. The bipartisan group has been able to broker tough compromises before, including solutions to end government shutdowns, but it wasn't clear Wednesday that it could get a breakthrough on immigration, an issue that has become fraught with political peril.

Democrats had their own concerns about the latest moderate proposal. During a caucus meeting Wednesday night, Durbin recounted that many of his members were struggling to accept some of the provisions in the bill, including the one that prevents DACA recipients from sponsoring their parents for citizenship if those parents had brought them to the US illegally.

"We still have to solidify our caucus," Durbin said.

Sen. Heidi Heitkamp, a moderate Democrat from North Dakota, said that at this point leaders weren't twisting arms to get their caucus on board.

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"Leadership is saying, 'Look, this is a group of people ... who have met for a long time. There are compromises in here that are difficult for a lot of people, and yet a real opportunity to go forward,' " Heitkamp said. "What they're saying is you're going to have to vote your conscience, but they think that this is the best they think can be done in a short period of time."

What will the President say?

Republicans weighed whether they could back a proposal that didn't address all four "pillars" the White House wanted -- including an end to the diversity visa lottery and an overhaul of legal immigration.

"We are looking at it. My staff is looking at it," Sen. John Cornyn, a Texas Republican, said of the White House proposal. "We ought to review it and consider it."

Asked if he supported a more narrow deal, however, Cornyn responded, "No, I support the President's proposal."

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Those working on the bipartisan plan faced serious pushback throughout the day from the White House -- and from Republicans firmly behind a plan from Iowa's Sen. Chuck Grassley that includes all four pillars.

Their pitch was as unified as it was simple: There is only one proposal the President supports, there is only one proposal the President will sign and as such, there's only one proposal the more conservative House Republican leadership would be willing to take up.

At one point, the office of Sen. Thom Tillis, a North Carolina Republican who's a member of the bipartisan working group, sent out a handy chart to reporters titled "Can the proposal become law?" Under the heading "Does the White House support it?' there were lines drawn to two boxes, one that said "yes" and one that said "no."

The message wasn't subtle: The bipartisan proposal, in the eyes of many Republicans, was dead on arrival due to the White House position.

Early Wednesday, Trump backed the Grassley plan in no uncertain terms.

"I am asking all senators, in both parties, to support the Grassley bill and to oppose any legislation that fails to fulfill these four pillars -- that includes opposing any short-term 'Band-Aid' approach," Trump said in a statement.

Asked how he felt about the bipartisan measure, Sen. David Perdue, a Republican from Georgia, who is backing the Grassley proposal, said the Iowan's was the "only serious bill I see on the floor so far."

"I'm getting concerned that the other side doesn't really want to solve this," Perdue said.