Feeling like a political prisoner at the in-laws' house
No matter how bad it is, it's just a few days, and will end. Even if your means of coping is to stand in the middle of the room and yell STOP IT STOP IT STOP IT until the gathering descends into total mayhem, it's just a few days, and will end.
It will be fine.
You will be fine. Maybe miserable for a while, but fine.
So you have two options for handling the trip in a rational manner: Either put off thinking about it until you actually embark on the visit, figuring you'll just tough it out -- or spend a day or so discussing a few strategies with your husband now so you don't have to think about it anymore. "I'm stressing about this. I want to make a plan early so I can be free not to think about it again."
May I suggest:
-- Leave the room. Every time. Go for a walk, do the dishes, grab a book and retreat to the guest room.
-- "Please, let's not talk about politics." Repeat verbatim as needed.
-- Talking about politics. It might unravel quickly, but maybe that's preferable to mounting tension and weather talk.
Whatever you decide, just decide. Torturing yourself for months now over a few days then just defies logic and wears you down.
And as with anything stressful, try finding a positive side, too, even in a small way -- like with your in-laws. Where do you agree? Or tune up your coping skills. What calms you: good books, movies, music, dance, exercise, friends, comedy, yoga, meditation, good deeds? Why just get by when you can get better.