WASHINGTON — As the Senate struggles to find an immigration bill it can pass, two new bipartisan proposals are being rolled out, both containing some of President Donald Trump’s demands but parting on others.

The fate of those plans was clouded even before their release as the president issued a plea to senators Wednesday to support his proposal, which was introduced as a bill by Sen. Chuck Grassley, R-Iowa.

"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.

Democrats left an early evening caucus meeting about the proposals Wednesday unenthusiastic about either choice and many, especially the more liberal members, were still uncommitted. There is also doubt by both senators and aides that even if it does gain the support of nearly all 49 Democrats. There wouldn’t be enough Republican support to reach the 60-vote threshold needed for passage.

"This is one of the hardest issues Congress has had to grapple with in recent years," Senate Minority Leader Chuck Schumer said in a statement. "Each side has to give a great deal, but we are closer than we have ever been to passing something in the Senate to help dreamers.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Groups of senators from both sides of the aisle have been meeting consistently since the impasse over those immigration issues led to a short-term government shutdown last month.

One proposal, likely to be introduced by Sen. Mike Rounds, R-S.D., emerged from the so-called Common Sense Caucus. It is a pared down version of Trump's four-pronged proposal. Like Trump's, it would provide a path to citizenship over 12 years for 1.8 million Dreamers and provides $25 billion for border security over ten years.

"I've had to ask myself many times, 'What are you willing to swallow to give 1.8 million dreamers a path to citizenship," Sen. Dick Durbin, D-Ill., said. "To me, the painful provisions in here, even this embarrassing wall — that he would start such a thing — are part of what it takes when you're in the minority."

The bipartisan plan also addresses family-based migration but is much more limited than what the president wants. Instead of limiting family migration for all new citizens, which would dramatically reduce legal immigration, it would only affect the parents of Dreamers, who would not be able to petition for legal status because of their children's new citizenship. It also differs from the president's because it does nothing to change the diversity visa lottery, which the president wants to end.

"It is our hope that, since our bill is bipartisan, and we’ve incorporated priorities from both sides of the aisle, that we will be able to get a good vote. But you just never know," Sen. Susan Collins, R-Maine, who launched the Common Sense Caucus that met multiple times a week and fueled by cookies.

Another new bipartisan proposal, by Colorado's two senators — Republican Cory Gardner and Democrat Michael Bennet — is even more limited. It addresses border security and the DACA program. It also gives 1.8 million Dreamers a 12-year path to citizenship and $25 billion for border security. In addition, it adds immigration judges and lawyers and instates a voluntary E-verify program for employers to check the legal status of their employees.

"This amendment is a reasonable solution to break through Washington gridlock and provide a compromise for Dreamers who are counting on us in Colorado and around the country,” Bennet said of his proposal.

Senate Majority Leader Mitch McConnell, R-Ky., put his weight behind the Grassley measure at the beginning of the week, however, making the success of any bipartisan proposal less certain. Grassley's bill is partisan and is unlikely to gain the support of any Democrats except for Sen. Joe Manchin of West Virginia, who indicated earlier in the week that he's likely to support it.

Further tipping the scales against any bipartisan measure, Sen. John Cornyn, R-Texas, told reporters Wednesday that the last vote Republicans are expected to bring up is the Grassley proposal, ensuring that they will likely hold their votes for any proposal voted on before it.

Sen. Jeff Flake, R-Ariz., said he was skeptical that the bipartisan Rounds bill could get the necessary 60 votes in the Senate, but he wasn't sure of it. "It kind of depends on the order in which they come up, too," he said.

The Senate will likely start voting on all the amendments on Thursday.