Immigration reform advocates are keeping the heat on key Senators to act quickly on a new legislative package, saying time is short to get anything done this year.

Despite scoring a couple of successes in recent days — the unveiling of a bipartisan proposal by Sens. Charles Schumer (D-N.Y.) and Lindsey Graham (R-S.C.) last week followed by a large rally Sunday on the National Mall — reform advocates are worried it will get increasingly difficult to move legislation with each day that passes before the midterm elections.

“The moment of truth will come soon,” said Frank Sharry, founder of the immigrant advocacy group America’s Voice. “There is either the decision to move forward, or not. We’re throwing down.”

Reform supporters are planning several rallies on the West Coast in April and May, along with a massive grass-roots push to persuade Members to act quickly.

America’s Voice is also planning a small inside-the-Beltway cable television ad buy this week, according to Sharry.

Schumer, who chairs the Judiciary Subcommittee on Immigration, Refugees and Border Security, had hoped to introduce a bipartisan bill by January. He and Graham have been working quietly to build a bipartisan coalition to support the bill.

Subcommittee ranking member John Cornyn (R-Texas) said through spokesman Kevin McLaughlin that he “applauds the work of his colleagues in putting together these principles.”

But McLaughlin added, “Until there’s legislative text and active presidential leadership, comprehensive immigration reform is unfortunately going nowhere this year.”

Indeed, Graham is the lone Republican on board so far, and Friday he warned that health care may cripple the bill. Others in the GOP have asked for more details.

“My No. 1 concern is to protect our borders and decide what to do with the people who are already here,” Sen. George LeMieux (R-Fla.) said.

LeMieux also warned that the reconciliation process in the Senate to pass health care reform could poison the waters for bipartisanship on every issue for the rest of the year — a concern echoed by Graham.

“The first casualty of the Democratic health care bill will be immigration reform,” Graham said in a statement.

Members from both sides of the aisle are looking to President Barack Obama to take the lead on immigration, an issue that in the past has forged bipartisan alliances and ripped others apart.

Graham spokesman Kevin Bishop referenced quotes his boss made during a March 14 interview on ABC’s “This Week,” when the South Carolinian instructed Obama “to do the heavy lifting.”

“You put together a comprehensive immigration reform package,” Graham said in that interview. “You bring it to the Senate and House and see how many Democrat and Republican supporters you can get. All you have done is talk about what we should do. Now is the time to lead.”

At a White House meeting March 11 with Schumer and Graham, Obama pledged to help the duo secure another Republican supporter — considered a must for any legislative action to occur this year. Obama also had separate meetings the same day with 10 immigrant advocacy groups and members of the Congressional Hispanic Caucus, all in an effort to show his passion for the issue to constituencies that are frustrated with the lack of progress this year.

Immigration reform groups said they would focus their energy on Senate Republicans following the strong public statements by Obama and Senate Majority Leader Harry Reid (D-Nev.) supporting Schumer and Graham’s efforts. Congress has tried with little success in the past to pass comprehensive immigration reform. Senators appeared to be close to a deal with the Bush administration in 2007 before conservative opposition stymied an agreement.

Reform advocates say they are much better organized this year, with a grass-roots network that can be mobilized through text messaging, micro-targeting and e-mail.

“Nobody gets a pass,”said Gabriel Gonzalez, campaign director for the Center for Community Change. “At this point, everybody needs to stand and be counted.”