Republican presidential candidate former House Speaker Newt Gingrich talks with the media during a stop at his campaign office, Thursday, Dec. 29, 2011, in Sioux City, Iowa. (Eric Gay/AP)

Conservative Christian leaders Jim Garlow of Skyline Church in San Diego and Don Wildmon of the American Family Association, both of whom are supporting Gingrich, also participated in the call.

In a letter sent to pastors inviting them to call in, Wildmon emphasized Gingrich’s “thrust to remove elitist judges who ignore the American people, like the three Iowa Supreme Court justices who voted in 2009 to impose homosexual marriage on all Iowans.”

Gingrich is fighting for Iowa’s influential evangelical vote -- which accounted for about 60 percent of Republican caucus-goers in 2008 -- but he’s facing heavy competition from former senator Rick Santorum of Pennsylvania, who is enjoying a surge in the polls; Rep. Michele Bachmann (R-Minn.); and Texas Gov. Rick Perry, who has spent hundreds of thousands of dollars airing ads avowing his Christian faith and criticizing the admission of gays to the military.

In current polls, in fact, the conservative vote is so splintered that the candidate who is least popular among this sizeable constituency -- former Massachusetts governor Mitt Romney -- is leading the field.