Here's something everyone knows: Social media is driving American politics into a ditch of partisanship. Political junkies log on and cocoon themselves in a bubble of friendly punditry, appealing fake news, and outrageous acts from the other side. Every retweet and every like is another moment of identity confirmation, another high five to our friends, another reminder that we're right and they're wrong.
The result is, well, this ugly mess — President Donald Trump, red and blue Americas, polls showing we fear and hate the other party more than ever before, conspiracy theories growing like weeds, a polity where agreement is impossible and everyone is angry. Damn you, Facebook! Curse you, Twitter! (Instagram, you're cool.)