A group of 40 House Republicans for the first time Wednesday encouraged Congress’s deficit reduction committee to explore new revenue as part of a broad deal that would make a major dent in the nation’s debt, joining 60 Democrats in a rare bipartisan effort to urge the “supercommittee” to reach a big deal that could also include entitlement cuts.

The letter they sent represents a rare cross-party effort for the rancorous House, and its organizers said they hoped it would help nudge the 12-member panel to reach a deal that would far exceed the committee’s $1.5 trillion mandate.

Among those who signed were several dozen Republicans who had previously signed a pledge promising they would not support a net tax increase. Among the Democratic signers were some of the House’s most liberal members who have opposed entitlement cuts.