Republicans argue that some of the voters’ concerns are justified because, they say, the proposals before Congress do not spell out procedures to verify the citizenship of those who would receive health coverage.

After testing their ideas with voters during the recess, Republicans said they would press for verification measures when the health care debate picks up again in Washington…

“A lot of their kids are in the school system,” Mr. Gingrey said in a telephone interview. “They get a free public education without any question. My constituents don’t want the same thing to happen with regard to health care.”…

Mr. Grassley said he would push to include citizenship verification for all applicants as part of a broad renegotiation of the Senate proposal when Congress reconvenes.