The program, sponsored by a temporary entity called the Iowa Renewal Project, featured several superstars of the Christian right as well as four possible Republican contenders for president. It was the latest of dozens of free, two-day conventions in at least 14 states over the past several years, usually with Mr. Huckabee listed as a co-sponsor, that have been attended by nearly 10,000 pastors who have spread the word in their churches and communities.

These meetings are part of a largely quiet drive to revitalize the religious right by drawing evangelical pastors and their flocks more deeply into politics — an effort given new energy by what conservative church leaders see as the ominous creep of laws allowing same-sex marriage and their sense that America is, literally, heading toward hell.

The Iowa pastors heard David Barton, a Christian historian, argue that the country was founded as explicitly Christian and lament that too few evangelicals get out and vote. They heard Newt Gingrich, a former House speaker and like Mr. Huckabee a possible 2012 presidential candidate, say that constitutional liberties like the right to bear arms were ordained by God. They heard how to promote “biblically informed” political advocacy by churchgoers within the confines of federal tax law.

The other possible candidates who spoke were Gov. Haley Barbour of Mississippi and Representative Michele Bachmann of Minnesota.