Updated: 4:59 p.m.

A trio of leading Democratic Senators on Wednesday began working on contingency plans for pushing a Democrat-only immigration reform bill if they are unable to convince Republicans to join the effort this year.

Majority Leader Harry Reid (Nev.), Democratic Conference Vice Chairman Charles Schumer (N.Y.) and Democratic Senatorial Campaign Committee Chairman Bob Menendez (N.J.) floated a summary of the legislation to immigration groups Wednesday. The package would require that a series of new border security benchmarks be met before broader immigration reforms are enacted — including a legalization process for illegal immigrants, according to a copy of the summary obtained by Roll Call.

The measure would also include tough new rules governing the hiring of illegal immigrants and on visas for both high-tech and low-skill immigrant workers.

Reid, Schumer and Menendez are pursuing a Democrat-only route at the same time that Schumer engages in a new round of meetings with possible Republican supporters of an immigration overhaul, including Sens. Scott Brown (Mass.), George LeMieux (Fla.), Lisa Murkowski (Alaska), Judd Gregg (N.H.) and Dick Lugar (Ind.). A Democratic Senate aide said Democratic leaders wanted to ensure they had an alternative in place if Republicans decline to join Schumer’s efforts.

Under the Democrats’ plan, Reid, Menendez and Schumer would sponsor the bill along with Majority Whip Dick Durbin (D-Ill.) and Sen. Dianne Feinstein (D-Calif.), who is the second ranking member of the Judiciary Subcommittee on Immigration, Refugees and Border Security.

Immigration reform advocates would work separately to press Republicans and moderate Democrats to support the package, the aide said.

Reid spokesman Jim Manley said the draft “reflects months of bipartisan work,” adding that “it is not a Democrat-only bill but is intended to serve as an invitation to Republicans to look at it and sit down to solve problems with us.”