Washington (CNN) A group of bipartisan senators Wednesday struck a much-anticipated deal on a narrow immigration compromise -- but it remains unclear whether the proposal could garner the elusive 60 votes needed to advance legislation in the Senate.

According to a draft obtained by CNN, the bill would offer nearly 2 million young undocumented immigrants who came to the US as children before 2012 a path to citizenship over 10 to 12 years.

The plan, negotiated for weeks among moderate lawmakers, would also place $25 billion in a guarded trust for border security, would cut a small number of green cards each year for adult children current US green card holders, and would prevent parents from being sponsored for citizenship by their US citizen children if that child gained citizenship through the pathway created in the bill or if they brought the child to the US illegally.

Democratic senators huddled to talk over the proposal in a closed-door meeting Wednesday evening, and came out reluctantly hopeful about its prospects.

No. 2 Democrat Dick Durbin said it wasn't a "slam dunk" that all Democrats would support it.

"We still have to solidify our caucus," Durbin said. "There's some really strong feelings."

North Dakota Sen. Heidi Heitkamp, a moderate member of the bipartisan group, said Democratic leadership is not asking everyone to vote for the deal, but encouraging folks to get behind it.

"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."

Hawaii Sen. Mazie Hirono, a pro-immigration advocate on the left, seemed to be a reluctant yes, but noted there's a "huge compromise" that must be made.

"There are a lot of things in it of course I have been against," she said, noting the $25 billion trust and the parents provision. "So it's going to be a huge compromise. But you know what, I keep uppermost the need to protect the Dreamers and we're talking about 1.8 million people so that goes a long way toward swallowing the compromise."

Delaware Sen. Chris Coons, another bipartisan group member, acknowledged the deal has "very hard concessions," but that he is a yes.

Both said they want a vote on Coons' narrower bill with Arizona Republican Sen. John McCain to show support for that proposal, knowing it's not likely to get 60 votes.

But Coons said he was "hopeful" that enough Republicans could support the bill. If every Democrat voted for it, 11 Republicans will be needed to reach 60, and more would be needed for Democratic nos.

Trump reinforces stance

It's still unclear if the bipartisan approach would be able to garner the needed 60 votes to pass, however.

Senate Majority Leader Mitch McConnell explained why he supports a "four pillars' approach, addressing problems of both illegal and legal immigration.

"Common sense dictates we cannot simply treat one symptom of our broken immigration policy in complete isolation. We must address the underlying problems as well," he said. "That means fixing broken parts of our legal immigration system."

And President Donald Trump has been clear that he doesn't want anything short of a four-pillar solution-- one that includes border security, protections for DACA recipients, an end to the diversity lottery and a massive overhaul of the country's legal immigration system.

The inability of the bipartisan group to put a bill on the floor for a vote has frustrated Republicans who said they were stunned that after months of negotiations, the group wasn't ready. Many Republicans back a bill from Sen. Chuck Grassley, R-Iowa, that is supported by Trump, which would lead to a pathway for citizenship for 1.8 million people in return for $25 billion for border protection and significant changes to "chain" migration and the diversity visa lottery. That measure is also unlikely to get 60 votes.

But on a call with reporters Wednesday, White House officials declined to explicitly answer a question about whether Trump would veto a proposal that doesn't match what the administration has demanded, saying he's been clear he wants all four pillars and his approach.

Even without a formal veto threat, it's unlikely a bill the President doesn't actively endorse would pass both chambers of Congress.

Bill from Colorado senators

Also Wednesday, a new effort emerged from the bipartisan Senate delegation from Colorado -- Sens. Cory Gardner and Michael Bennet -- but as of that night, the proposal wasn't even scheduled to have a vote during the abbreviated Senate floor debate.

The amendment was offered Wednesday and represented a narrow approach to a deal -- a pathway to citizenship for young undocumented immigrants similar to other proposals and the creation of a $25 billion trust for border security. The bill would also restrict that money to only its designated purpose and require annual reporting from the government on the border.

The bill also included a couple of small pieces to gain additional support.

It would boost the number of immigration judges and attorneys to try to work down the immigration court backlog, which contributes to undocumented immigrants being left in the US for years as they await hearings, and it would also make voluntary worker verification systems permanent -- a concession to Republicans but far short of the mandatory use of the e-verify system for every employer that hardline conservatives have long demanded.