Two conservative groups are pushing back on moves by the GOP to drop opposition to same-sex marriage from party platforms, releasing a poll of base voters taken last month that found in favor of defining marriage “only” as between a man and a woman.

The poll, commissioned by groups led by conservatives Gary Bauer and Tony Perkins, runs counter to a wide variety of opinion polls that show movement on the question of same-sex marriage, with more voters favoring it than opposing it.

Last week, the Nevada GOP removed opposition to same-sex marriage from its platform, with the state chairman saying the move was indicative of where the party is headed.

The survey by the GOP polling firm Wilson Research Strategies was of Republican and Republican-leaning independents and was taken over a month ago, sampling 801 people from March 18 through March 20, with a 3.5 percent margin of error.

The survey showed 82 percent agreeing with a statement that marriage should be between “one man and one woman.” It also found 75 percent disagreed that “politicians should support the redefinition of marriage to include same-sex couples.”

A number of Republican influentials and elected officials have voiced support for same-sex marriage, and public polling has show independent voters increasingly supporting it.

At the recent Conservative Political Action Committee gathering in Maryland, the topic was mentioned far less frequently than it was in the past. But same-sex marriage supporters acknowledge it remains a difficult issue with a number of the party’s base voters, although they’ve argued for focusing on inclusion to broaden the GOP’s appeal after getting battered in the 2012 elections.

Bauer, the president of American Values, faulted a “misinformation campaign waged by media elites” and insisted that “public policy-makers are doing a great disservice to themselves and future generations by continuing to misread the convictions of the American people … this survey should remind political and cultural leaders that this debate is far from over. If anything, it is taking on a new sense of urgency for millions of men and women of faith.”

Perkins, the president of the Family Research Council, added that the “vast majority of the GOP base continues to believe that marriage is a non-negotiable plank of the national platform and want to see their elected officials uphold natural marriage as the national standard, a goal to stand for, encourage and promote in law.”