WASHINGTON  Conservative Republicans in the House plan to urge their colleagues to rally behind a new manifesto that mixes antispending initiatives and tighter restrictions on government benefits as the party seeks a fresh message after a string of election defeats.

Leaders of the Republican Study Committee intend to use a closed-door party meeting on Tuesday to present a seven-point proposal calling for a constitutional limit on federal spending, a new simplified income tax alternative and a proposal to require recipients of food stamps or housing aid to meet work requirements.

“Clearly, we have been sobered by three special election losses in a row,” said Representative Jeb Hensarling of Texas, chairman of the group of more than 100 Republican lawmakers. “We are sobered by the massive cash advantage that Democrats have to get their message out.”

Mr. Hensarling said that getting off the political defensive would “take unity, and it is going to take unity behind a handful of messages.”