In a tidy coincidence, two separate videos went viral last week, demonstrating that American Jews’ love affair with obscenity is still going strong. Sarah Silverman talks about being visited by Jesus Christ, who asks her to spread a message about women’s reproductive rights (“We’ve got to legislate that shit,” the comedienne said, mocking conservatives who want to use the law to limit women’s health care options), while a a fan-produced supercut strung together three minutes of uninterrupted insults by Larry David on "Curb Your Enthusiasm."

As far as I know, only Silverman has publicly called herself a “dirty Jew,” purring the words alluringly in her 2005 performance film "Jesus Is Magic," but David’s gleeful, exuberant and inimitable spewing of obscenities suggests he might not exactly mind being thought of as a dirty Jew, either.

In my recently published book, “Unclean Lips: Obscenity, Jews, and American Culture,” I explain why, beginning in the late 19th century, American Jews have found the explicit representation of sex, and four-letter words, so very useful. The answers vary: Some Jews use obscenity to fight anti-Semitism, while others use it to rewrite traditional Jewish stories in a contemporary idiom.

Silverman and David suggest another reason, one that’s specific to our own historical moment, which can be understood if we look at who’s fighting for tighter controls on obscenity in America today.

If you watch cable television and listen to podcasts, you might think that there’s no longer any regulation of obscenity in the United States at all. But the Protect Act of 2003 introduced several new prohibitions on sexual representation, particularly of minors, and also reinforced others. The Supreme Court’s decisions in the FCC v. Fox cases in 2009 and 2012 reaffirmed the mandate of the Federal Communications Commission to levy huge fines on broadcasters who allow even “fleeting” obscenities to air – even a dirty word tossed off, spontaneously, during a live broadcast.

Moreover, the decision rendered in Bethel v. Fraser (1986) still stands, making clear that in or near American public schools, First Amendment protection cannot be guaranteed to anyone using sexual innuendo, no matter how silly: The defendant here was disciplined for a campaign speech that began, “I know a man who is firm – he’s firm in his pants, he’s firm in his shirt, his character is firm.”

So, who’s behind the tightening of American obscenity laws in the 21st century? Like Anthony Comstock’s crusade against smut in the late 19th century, this one is understood by many of its leaders as a Christian project.

The late Democratic Senator James Exon of Nebraska, for example, sponsored what can be understood as the first major attempt at Internet-age, anti-obscenity legislation: the Communications Decency Act of 1995. Exon opened congressional debate about the act by repeating a prayer offered by televangelist Dr. Lloyd John Ogilvie, then Senate chaplain, who had asked “Almighty God, Lord of all life" to "give us wisdom to create regulations that will protect the innocent.”

Exon was also reported at the time as appreciating the work of Enough Is Enough, an anti-pornography group: The organization helped in “laying the groundwork for compromise between Christian conservatives and pro-business Republicans” in support of the act. Furthermore, the senator introduced into the Congressional Record letters of support for his proposal from Evangelical groups like the Christian Coalition and the Family Research Council.

For his part, Comstock often perceived Jews, in particular, as the spreaders of smut in America, and part of what inspired his activities was clearly a fear of people who didn’t seem Christian or American enough.

The contemporary Christian right has a much more complex and self-aware relationship with American Jews than its 19th-century predecessors did, though. So recent anti-porn campaigns have welcomed with open arms any Jews with compatible ideas, like Orthodox modesty crusader Wendy Shalit. Today’s anti-porn organizations, even if funded by Christians, often seek out Jews to sit on their boards – though mostly they attract only very marginal rabbis and other Jewish crackpots.

There are times, too, when you can almost but not quite hear echoes of Comstock’s anti-Semitism in contemporary discussions of obscenity. Writing for the majority in the 2009 FCC v. Fox decision, Justice Antonin Scalia made an odd remark about the relative use of taboo language among Americans of different backgrounds. He was rebutting a point from a dissenting opinion about how “small-town broadcasters” would suffer unduly under the court’s decision, because it would necessitate their purchase of expensive equipment to bowdlerize fleeting expletives during live broadcasts. These “small-town broadcasters” would not suffer, Scalia countered, because their “down-home local guests probably employ vulgarity less than big-city folks [and the] foul-mouthed glitterati from Hollywood.”

Dirty words, Scalia declared absurdly, aren’t a temptation for “down-home,” “small-town” American; they’re only a “big-city,” “Hollywood” problem. Scalia did not, of course, go so far as to suggest that the one demographic group most insistently associated both with American “big-city” life and with “Hollywood” – Jews – tend to speak more obscenely than other Americans. If he had wanted to, though, he could not have a better illustration of his hypothesis than Larry David and Sarah Silverman.

These Christian campaigns against obscenity – and the vague, recrudescent sense promoted by Scalia’s remark that the people using obscenity are not sufficiently Christian or authentically American – may help to explain why, in a media environment in which the representation of sex and the use of taboo language smacks increasingly of banality, brilliant performers like David and Silverman continue not only to assert their Jewishness emphatically, in virtually every one of their performances, but also to glory in and glorify the use of such language. Especially because the Christian right goes to such great lengths to demonstrate that Jews should not feel excluded from its initiatives – who loves Jews nowadays more than the Christian right, right? – identifying oneself as a “dirty Jew” in 21st-century America is one way to signal your opposition not just to the banalities of the market-driven family-friendly culture, but also to the nation’s most powerful socially, religiously and politically reactionary movement.

The writer is academic director of the Yiddish Book Center and visiting assistant professor of English at the University of Massachusetts, Amherst. He is also author of "American Jewish Fiction" (2009). Follow him on Twitter @joshnlambert