It's always been there. Remember, even Jefferson and Adams, best of friends, had their falling out over politics and became very bitter towards each other, before finally renewing their friendship at the end of their lives.

Then there is the famous story of Jimmy Stewart and Henry Fonda. Best friends who one night got into such an argument about politics that it turned into a fistfight. Afterwards they swore to never talk about politics again so that they could resume their friendship, and according to them they never did.

I think there is something about politics that really gets most people. I'm not quite sure what it is. But yes, the environment of today — especially social media — has stroked the flames and made it far worse.