Donald Trump has signed a pledge to crack down on pornography if he's elected president, according to a group that campaigns for the enforcement of federal laws that arguably criminalize distributing images of sexual activity among consenting adults.

Porn business owners say they doubt that the thrice-married Republican candidate who once posed for the cover of Playboy magazine actually would bring down the hammer, even if his signature on the document does appear authentic.

Much of the pledge drafted by Enough Is Enough deals with child exploitation. Its aim can be confusing at first, though it does specifically address federal obscenity laws and the possible societal harms of pornography in "whereas" clauses and in the pledge itself.

In signing, the group says Trump promised to steer more resources toward prosecutions and to appoint an attorney general who would make enforcement of federal obscenity laws – along with laws against child abuse and child pornography – "a top priority."

"We wanted it to be easy to say yes to and hard to say no to," says Enough Is Enough's president and CEO, Donna Rice Hughes.

Hughes says combining the policing of raunchy footage of consenting adults with advocacy against child abuse makes sense, citing what she says are high rates of teens viewing bestiality and group sex, and the potential that viewing hardcore porn could be a steppingstone to further depths.

"Bestiality and anal sex online, that's the new normal," she says. "This entire sex industry is tied together, so it's like fighting the drug war ... just completely ignoring the obscenity laws [but combating child porn] would be like saying, 'We've got a war on drugs, but we're only going to concentrate on meth and heroin.' That's not going to do a very good job."

Though theoretically possible, pornographers say they aren't concerned about Trump putting them out of business or in jail.

"I'm not too worried that the ultimate misogynist Donald Trump would enforce the obscenity laws, as I'm quite sure he has no idea what they are," says Steven Hirsch, founder and co-chairman of Vivid Entertainment, a large pornography company.

"One would think Mr. Trump's time would be spent on building fake walls and deporting immigrants," he says.

Hirsch says parents, rather than the government, should be responsible for preventing children from watching pornography, and that they have many software options available to filter or block such content.

Michael Lucas, a self-identified gay conservative and CEO of the gay porn company Lucas Entertainment, is similarly unconcerned.

"We hear the same kind of dialogue about porn every time a Republican runs for office, and those puritanical promises are quickly forgotten after the election," he says. "If Trump is actually concerned about protecting Americans from obscenity, he may want to earnestly consider that suggestion to delete his Twitter account."

Lucas, a U.S. citizen born in the former Soviet Union, adds: "I would not be voting for Trump even if he signed a pro-pornography pledge. I am not a single-issue voter. And honestly, I do not think any intelligent person who loves America can vote for Trump."

Donald Trump holds up a Playboy magazine before autographing it following a campaign rally on April 25, 2016, in Wilkes-Barre, Pa. Christopher Dolan/The Times & Tribune/AP

Unbeknownst to many Americans, pornography is not as legal as it seems. The Supreme Court affirmed in the 1973 Miller v. California decision that obscene content is not protected by the First Amendment, and federal obscenity laws remain on the books.

Justices also established a three-part test for what counts as obscene in the Miller ruling, allowing the restriction of content if it appeals to "the prurient interest" according to community standards, if the images portray sexual activity specifically defined by a law in a "patently offensive" way; and if the work lacks "serious literary, artistic, political, or scientific value."

The community standards prong means a pornographer hauled before a San Francisco jury likely would fare better than one targeted by Utah prosecutors, as jurors subjectively define obscenity.

There have been very few prosecutions of mainstream pornographers since former President Bill Clinton took office, following a more aggressive approach during the Reagan and George H.W. Bush administrations. In one rare recent case, which began under the George W. Bush administration, the Justice Department in 2012 won a guilty verdict in Los Angeles against a fetish porn producer who made videos of sex acts featuring bodily waste and animals.

"[I]t is illegal to sell and distribute obscene material on the internet," the Justice Department says on its website. "Convicted offenders face fines and up to five years in prison." And though the Supreme Court ruled in its 1969 Stanley v. Georgia decision that mere private possession of obscene content is protected by the First and 14th Amendments, the Justice Department cautions the act of receiving pornography still could be a crime.

Trump's signature is dated July 16. His spokeswoman, Hope Hicks, did not respond to a request for comment, but the signature appears similar to ones he placed on other documents.

The Republican nominee's assent to the pledge comes as somewhat of a surprise. Last year, most GOP candidates ignored a survey put out by another anti-pornography group, the National Center on Sexual Exploitation, asking for their positions. That group is led by former Justice Department prosecutor Patrick Trueman, who proudly participated in pornographer prosecutions in the '80s.

In the 2012 race, when leading Republican candidates promised to enforce federal obscenity laws, it brought them little positive press, and pornographers brushed off threats by former Sen. Rick Santorum of Pennsylvania and ultimate GOP nominee Mitt Romney. Last year, Santorum told U.S. News he did not recall saying he would vigorously enforce obscenity laws. "I don't even remember that position, to be very honest with you," he said. "I'm not, candidly, familiar with the federal laws with respect to pornography."

Still, anti-porn campaigners sense momentum, powered in part by reorienting talking points from morality to public health. In April, Utah's state legislature passed and GOP Gov. Gary Herbert signed legislation saying pornography is creating a public health crisis. Similar wording was adopted last month into the Republican Party's official platform.

Hughes says Democrat Hillary Clinton's campaign declined to sign on, citing a policy against making pledges, and says she doesn't doubt Trump's sincerity, despite his personal and business histories.

"Look, the past is the past. He was a businessman. He's running for president now," she says. "Mitt Romney was on the board of Marriott [when it was a major facilitator of on-demand porn]."

Hughes' name may be familiar to some for her role in past presidential politics. In 1987, she was pictured sitting in the lap of former Sen. Gary Hart, who was wearing a "Monkey Business" T-shirt. The image and allegations of infidelity helped sink Hart, who had been a front-runner for the Democratic nomination. Hughes says the ensuing media firestorm made her a more empathetic person.

"I was 29 years old and it was a very, very difficult time, and instead of talking to the media or selling out I chose to take the high road and return to my faith," she says, noting that she prayed the traumatic experience would produce something good. She joined Enough Is Enough in 1994, working initially under the radar before reporters recognized her.

Hughes now has worked more than two decades to make the internet a more child-friendly place. In the early 2000s, she helped with a Federal Prosecutors Symposium on Obscenity, put together by then-Attorney General John Ashcroft, a social conservative who famously ordered drapes to cover partially nude statutes in the Justice Department's main building.

"The pornographers have been laughing their way to the bank for years," Hughes says. "They're huge and it's getting worse. … What you need is someone who's strong and is going to put their foot down."

Hughes says Playboy magazine, which does not to her knowledge depict sexual intercourse, would not be obscene, but declines to say whether common, specific sex acts would be.

"Are you saying bestiality would pass community standards in every state of the union?" Hughes says. "I'm asking very clear for the obscenity laws and all the other laws – it's very important you get this in your article – that all of the laws are enforced. All of them."

Hughes says she personally would like to see a Trump administration do to the internet what former New York City Mayor Rudy Giuliani did to Times Square in terms of cleaning up crime. She's also a fan of former U.K. Prime Minister David Cameron, whose government required internet service providers to enact default porn filters, which could be turned off for customers who would like to see porn.

The anti-smut campaigner says the near impossibility of blocking foreign porn-hosting websites shouldn't deter the U.S. from taking action.