Matthew Putney/ABC

ABC's Michael Falcone, Shushannah Walshe and Elicia Dover report:

DES MOINES - As Newt Gingrich stood before a crowd of hundreds of social conservatives here less than three weeks before Iowans gather for the state's first-in-the nation caucuses, the challenge he faces came into stark relief.

Gingrich told the crowd on Wednesday night that he and like-minded Republicans were "engaged in a cultural struggle with a secular elite that believes that life is random and has no moral meaning."

But outside a historic auditorium in downtown Des Moines where Gingrich promised to support Congressional action to pass a bill that "defines personhood," critics of the former House Speaker placed pamphlets on car windshield that attacked Gingrich as a "a pro-life fraud."

The pamphlets, which were authorized and paid for by the group, Iowans for Life, accused Gingrich of campaigning for "pro-partial birth abortion candidates," urging "fellow Republicans to drop the pro-life issue because it was too divisive," and leaving any mention of abortion out of his book," Winning the Future."

"Newt Gingrich used his position as Speaker to keep taxpayer dollars flowing to Planned Parenthood, and has publicly stated he supports taxpayer funding for abortions under certain instances," the leaflets, printed on bright pastel-colored paper read.

Gingrich has recently been taking steps to consolidate his support among social conservatives and evangelical Christians.

Over the course of the week, he offered his support for two pledges: an anti-gay marriage vow created by the Iowa organization, The Family Leader, and a personhood pledge sponsored by the group, Personhood USA.

"The 14th Amendment clearly allows the Congress to define personhood," Gingrich said Wednesday night. "That should mean that we can pass a bill defining personhood as beginning at conception and we don't need a constitutional amendment."

Gingrich was one of four presidential candidates to address the forum in Des Moines - an event laden with imagery and songs that wove together themes of patriotism and conservatism with a staunchly anti-abortion rights message.

Audience members came not only to hear the presidential candidates but also watch a new documentary film, "The Gift Of Life," which was produced by the Washington, DC-based conservative group, Citizens United, and narrated by former Arkansas Gov. Mike Huckabee, who also spoke at the event.

Huckabee, who at this time four years ago was a presidential candidate just weeks away from winning the Iowa Caucuses, thanked the GOP contenders who showed up.

"I do want you to take note that there were four candidates that cleared their schedule and made this a priority event," Huckabee said. "All four of the candidates here tonight have endorsed life."

Regarded as something of a rock-star among the crowd on Wednesday night, Huckabee said in an interview that he had no intention of endorsing a candidate before the caucuses.

According to recent ABC News polling, Gingrich leads among evangelicals in Iowa, but their support still remains largely divided among several candidates. Their influence over the final outcome of the caucuses could be large if they unify. Four years ago, 60 percent of GOP caucus-goers identified themselves as evangelicals.

With that in mind, Texas Gov. Rick Perry, who opened a 42-city bus tour of Iowa on Wednesday, promised the crowd that he would "end taxpayer-money funded abortions. Period."

He highlighted his efforts to strip funding from Planned Parenthood in the Texas state budget.

"I can assure one thing if Washington, DC is looking for a fight they've found one," Perry said. "I won't back down from this fight as a governor, and if I'm lucky enough to be your president I won't back down either."

In her remarks, Michele Bachmann emotionally recalled her own miscarriage.

"The doctor placed that baby on a towel and placed that beautiful child who is a human being in my hand on that towel - that baby was perfect," Bachmann said. "I know without a shadow of a doubt every baby that God creates is perfect."

The Minnesota congresswoman, whose presidential hopes rest on her performance in the Iowa caucuses, called President Obama "the most pro-abortion president that we have ever had in our nation." She pledged to be the "most pro-life president" if elected.

Former Pennsylvania Sen. Rick Santorum drew loud applause for his firm stand against a so-called "truce" on social issues that seeks to help unify the fiscal conservative and social conservative wings of the Republican Party.

"I've been in the foxhole - out on the front lines - fighting the conservative fights on a national scale," Santorum said. "I fought, I fought in the trenches standing up for life."