AMES, Iowa – At the Family Leadership Summit in Iowa on Saturday, Republican presidential candidates addressed social conservative activists, who quizzed them on such topics as gay marriage, abortion, immigration, and foreign policy.
The event was overshadowed, however, by another outburst from Donald Trump, who told the crowd that Republican Sen. John McCain of Arizona was “not a war hero” because he was captured during the Vietnam War.
“He’s not a war hero,” Trump said during an onstage Q&A with the event’s host, Republican messaging guru Frank Luntz. “He's a war hero because he was captured. I like people that weren't captured, okay?”
Those comments prompted a backlash from party leaders, including many of the presidential candidates speaking at the event, far stronger than anything Trump has experienced since announcing his presidential campaign on June 17.
“Donald Trump owes every American veteran and particularly John McCain an apology,” former Texas Gov. Rick Perry said onstage.
RELATED: GOPers denounce Donald Trump amid fiery feud with John McCain
The event included no speeches from candidates, who instead took questions from Iowa voters and from Luntz, offering a window into the top concerns driving state Republican activists. As some activist leaders acknowledged in their onstage remarks, the summit comes at an uneasy time for religious conservatives.
Last month, the Supreme Court overturned gay marriage bans in all 50 states, capping a decade-long shift in which supporters of equality pushed their opponents towards the political and cultural fringe. Earlier this year, conservative activists working in states like Indiana to pass “religious freedom” laws designed to allow businesses and individuals to refuse to participate in same-sex ceremonies ran aground after hitting major opposition from corporations.
Wisconsin Gov. Scott Walker repeated his call for a constitutional amendment allowing states to ban gay marriage, a position that puts him at odds with rivals like former Florida Gov. Jeb Bush and Sen. Marco Rubio, who oppose taking the fight that far.
“I’ve had this opinion for more than 20 years,” Walker said. “I believe marriage is between one man and one woman.”
Sen. Ted Cruz of Texas called out unnamed rivals for being too content to drop the issue as well.
“You know, it was sad to see more than a few Republicans, including more than a few 2016 candidates publicly saying it's the law of the land, it’s settled, surrender and move on,” Cruz said. “There is something profoundly wrong when republicans running for president are reading from Barack Obama’s talking points.”
RELATED: Supreme Court rules in favor of marriage equality
Brian Brown, president of the National Organization for Marriage, tried to buck up audience members demoralized by the Supreme Court's decision.
“Did Frederick Douglass give up when he was fighting against slavery?” he said.
On abortion issues, however, things are less bleak for the right.
Republican majorities have managed to pass a raft of legislation targeting clinics with new restrictions and challenging courts on late term abortions. This week, pro-life activists launched a new offensive against Planned Parenthood with a hidden camera video showing a top official with the group, Dr. Deborah Nucatola, discussing how their clinics acquire tissue from aborted fetus for medical research. Planned Parenthood CEO Cecile Richards apologized for the official’s “tone and statements” in the footage, in which Nucatola bluntly described procedures from removing specific organs, but denied accusations from pro-life critics that her organization profited off the voluntary donations.
Cruz, who received a rousing reception from the crowd, brought the crowd to its feet by pledging to press the issue in the wake of the video.
“The US Department of Justice, if it were not simply a partisan arm of the [Democratic National Committee], should open an investigation and prosecute Planned Parenthood,” Cruz said, calling the tape “gruesome and disgusting.”
Walker noted that he had cut off state dollars for Planned Parenthood in Wisconsin as governor years earlier.
“I didn’t have the cover of a video to make the case why Planned Parenthood needed to be defunded,” Walker said. He told the audience that the group "promoted a culture of death.”
RELATED: Planned Parenthood releases video in response to accusations
Foreign policy also figured heavily into attendees’ minds. Recently, President Obama reached an agreement with Iran over its nuclear program, prompting outrage from a conservative Israeli administration that’s grown increasingly popular with the Christian right in America.
“We now live in a world where we treat the Ayatollah in Tehran with more respect than the prime minister of the only pro-American, free enterprise, democracy in the Middle East, the state of Israel,” Rubio, whose voice was weak due to an illness, said early in the summit.
“The times are dark, there’s a lot of really bad things happening, but I believe there is still a silent majority out there represented by you today,” Gary Bauer, a leader with Christians United for Israel, told the crowd.
Another leading topic among Iowa conservatives: The Islamic State. Many candidates drew applause pledging to mount an aggressive campaign as president to defeat the Islamic militant group that now controls large swaths of Iraq and Syria.
Asked about the recent Supreme Court decision on marriage rights, Foster Friess, a top donor to conservative causes and candidates, told msnbc his top focus was Islamic radicalism.
“I’m more interested, I think, in how do we protect the gay community from Sharia law?” he said.
“These are religious Nazis, they can't be dealt with, they have to be degraded and eventually destroyed,” Sen. Lindsey Graham of South Carolina said.
RELATED: 2016 Republicans bash Iran nuclear deal
Graham was one of several candidates lagging in state and national polls who nonetheless drew a strong positive response. Louisiana Gov. Bobby Jindal whipped the crowd into a frenzy with his appearance, peaking with a line delivered directly to the press seated near the front of the stage.
“I am critical when the mainstream media, they don’t apply the same standards to this president that they apply to the rest of us,” he said.
As Trump’s rise in the polls suggested, a number of voters asked candidates how they would crack down on illegal immigration, which has moved to the front of the political conversation in the state at Republican events. Candidates uniformly pledged to secure the border while largely sidestepping when or how to address the 11 million undocumented immigrants estimated to be living in the United States today.
Former Sen. Rick Santorum of Pennsylvania garnered light applause with his call to cut back legal immigration by 25% -- so far he’s the only contender to call for such reductions.