By Katy Steinmetz, Time

Chris Adamson is a let-live libertarian, but he didn’t mind that most of his Facebook friends are uberliberal–until this election season. That’s when the Grand Rapids, Mich., computer programmer noticed a stream of less-than-subtle posts invading his News Feed.

The breaking point came when one of his buddies pledged to post every single day in an effort to understand “why his friends could possibly vote for” Mitt Romney. “Given the nature of my friend group, I’m getting this very one-sided argument that I don’t even want to participate in anymore,” Adamson says.

Politics, classic etiquette tells us, is a subject best avoided when friends come to dinner. It may be time to amend that advice to include Facebook. The Pew Research Center found that nearly 1 in 5 social networkers has blocked, hidden or unfriended someone over political material that was too frequent or too disagreeable.

Though social networking played a big role in the 2008 race, spurring fundraising and helping candidates get out their message, it was still the province of earlyish adopters. Since then Facebook has grown tenfold; it just hit 1 billion monthly users worldwide. Today’s bigger friend groups are also more diverse, which makes it easier to offend.

Some Facebookers have decided just to sever the online ties. Jake Sherlock, a communications coordinator in Colorado Springs, says he unfriended one of his long-distance in-laws over political chum. “The final straw for me was a post about how Obamacare requires all Americans to get chips installed in their skin,” he writes. A less drastic alternative is blocking a person’s updates from your News Feed so you don’t see their posts unless you go looking for them. Leslie Hassel, a graduate student at the University of Mississippi, says that “in an effort to salvage my relationship with my mother,” she has unsubscribed from posts by the “rabid Republican” who raised her.

Political oversharing is facilitated by what psychologists call the Internet’s disinhibition effect. John Suler, a psychology professor at Rider University in New Jersey, observes in an article for CyberPsychology & Behavior that people feel emboldened by the lack of real-time response and the sense that the things they do online are less serious than actions in the real world. We get on the Web, and “out spills rude language and harsh criticisms, anger, hatred, even threats,” Suler writes.

Etiquette gurus provide some guidelines for dealing with politics on Facebook. “Sharing what you like is generally better than sharing what you don’t,” says Anna Post, a scion of etiquette legend Emily Post. Also, now that many people can count everyone from close friends to crazy uncles to far-flung professional contacts among their Facebook friends, it’s important to keep the whole audience in mind, says consultant Jacqueline Whitmore. The original rule about politics and conversation, after all, was about having consideration for others’ feelings.

For his part, Adamson is fighting back in iambic pentameter. Every time one of his friends posts something political, he posts one line, in order, from Shakespeare’s Measure for Measure. “We’ll see if we get through the whole play by November 6th,” he announced on his wall in late September. At this point, he’s at least reached his favorite line, from Act II, Scene 1: “Some rise by sin,” the Bard wrote 400 years ago, “and some by virtue fall.”