In response to polling data showing that the Affordable Care Act has become more popular, a prominent Republican pollster said that he expected Republicans to change how they talked about the law.

“After the primaries, expect a shift in Republican candidates’ rhetoric against Obamacare,” said Bill McInturff, a partner in Public Opinion Strategies. “Only few want to repeal the law,” he said of voters. “Most want to fix and keep it.”

Mr. McInturff, speaking at the annual conference of the American Association for Public Opinion Research in Anaheim, Calif., was referring to results from survey work his firm does with Hart Research Associates for NBC News and The Wall Street Journal.

Mr. McInturff said he still believed the law would hurt Democrats in the midterm campaign. President Obama’s personal ratings suffered last November after the rollout of the health-care plan. Although there has been some recovery, Mr. McInturff does not believe there will be enough time before the midterm elections to repair the damage. He added that Mr. Obama’s incorrect assertion that people could keep their health-care plan if they wanted had appeared to be particularly harmful.