Ike Barinholtz’s “The Oath” is a filmgoing experience not unlike the nightmarish Thanksgiving dinner with relatives on the other side of the political divide that the film portrays — excruciating.

A satiric comedy that rarely lightens its shrill tone with anything like a laugh, it’s hardly a cinematic break for anybody looking to escape the tidal wave of cruelty, callousness, criminal stupidity and “America Worst” news to pour out of Washington these past few years. And for those not looking for a break? Heaven help you. The stress of endless “outrage” updates on your phone or on cable news is amped up by this miscalculated attempt at “The Movie America Needs to See.”

It’s not biting, it’s pummeling. And while it isn’t incompetent or terribly written, acted or shot, while its warning has the sting of “Yeah, we’re pretty close to that happening here,” it is just plain unpleasant to sit through.

Writer-director Barinholtz (TV’s “The Mindy Project”) stars as Chris, a hyper-sensitive, seriously-worked up LA marketing guy married to a like-thinker, Kai (Tiffany Haddish) and upset enough to declare “I will not ALLOW my daughter to grow up in a country like this!”

What he means by “like this” is a country that has leapfrogged a few steps down the ladder towards fascist totalitarianism and come up with a “Loyalty to my president” oath — promising perquisites for those who sign it, and rightly-feared penalties, harassment and worse for those who don’t.

Turn off Fox News for five minutes and accept that this idea has surely passed through the current chief executive’s head.

Kai is more concerned with “keeping my little girl safe,” and with keeping the peace. That’s the key to this upcoming Thanksgiving dinner. His parents (a clucking Nora Dunn and Chris Ellis) were quick to sign. He doesn’t even have to ask his “stupid” brother Patrick (Jon Barinholtz) or Patrick’s Eva Braun blonde girlfriend Abbie (Meredith Hagner, magnificently vile) if they signed.

Kai and Chris’s mother vow “No politics” at the weekend get together. Kai has to constantly remind Chris to step away from the TV.

It’s no use. His phone goes off with every fresh development — riots, civil rights violations by the newly formed CPU, “Citizens’ Protection Units.”

Chris shouts “LIES” at his car radio and finds himself trapped in one of the ugly situations a lot more commonplace these days — angry racist people (a road rager) emboldened by a bellicose bigoted bully in the White House, slashing tires and screaming “Get out of my country!”

His like-minded sister Alice (Carrie Brownstein) arriving with her sick-with-diarrhea husband (Jay Duplass) doesn’t balance the battle lines enough to suit Chris.

Dinner starts out with the old white people singing the praises of comic Bill Engvall, the knee-jerking Chris and Kai chortling that they prefer Chris Rock, whom Abbie and Pat describe as “racist.” Oh yeah?

“It’s racist to THINK Chris Rock is racist!”

An epic meal is slipping into chaos when two CPU guys (John Cho and Billy Magnussen) show up at the door wanting to have a little talk with Chris. This is the movie’s most troubling moment. A gun-averse, thinker-not-fighter liberal is confronted with two guys — one specifically (Magnussen of “The Big Short”) — refusing to leave, refusing to acknowledge how laws all the way up to the United States Constitution require them to leave, baiting the mouthy guy whose politics they aim to suppress by dropping the hammer on him.

It’s just that the violence they, or specifically Mason (Magnussen) intends to mete out backfires.

How do you extricate yourself from the legal problems of resisting, injuring and disarming pseudo-legal authority? And once you’ve committed violence, how far can a non-violent person go with it?

Magnussen is like every scary encounter you’ve ever seen on the news or had in person with a no-neck racist musclehead who agrees with a third of this country that his might or gun or badge permits him to lord over “elites” in any way he wants?

There haven’t been any real laughs before this sequence, and after it “The Oath” descends utterly into darkness. For a short movie, a supposed quick take on this subject with satiric intent, “Oath” drags thanks to its lack of “funny but scary-true” observations.

It’s almost a waste to cast Comic of the Moment Haddish in the film, and while she has little “believable couple” chemistry with Barinholtz (totally out of his league), she does get away from her “Girls’ Trip” shtick and show us something new.

As the violence escalates and the blood flows, the sharp if not-funny observations give way to “How can we extricate these people from this scenario in a way that makes sense?”

And Barinholtz the writer-director lets his straining against incredulity show. He utterly loses his nerve with the finale.

If you want to see how this sort of movie is supposed to work, track down the 1995 Canadian satire “The Last Supper,” about liberals moved to betray their non-violent values when confronted by a power-abusing right-wing talk show host (Ron Perlman).

That was dark, bloody, biting and funny. Unlike “The Oath,” which manages half of those.

MPAA Rating: R for language throughout, violence and some drug use

Cast: Ike Barinholtz, Tiffany Haddish, Nora Dunn, Meredith Hagner, Jon Barinholtz, Carrie Brownstein, John Cho, Billy Magnussen, Jay Duplass

Credits: Written and directed by Ike Barinholtz . A Roadside Attractions release.

Running time: 1:33