I wasn't there, but I've read that the years when the very first political parties defined themselves at the time of the Constitutional Convention were as vile a time for politics as they are today. They had duels, canings on the capitol steps, fistfights in chambers, character assassination, snooping private eyes, muckraking journalism, even open armed rebellion in some cases.
The last few years preceding the Civil War, people knew that collapse of the Union was unavoidable.
When we get to the point where we're openly egging on violent means against one another based upon political ideology, you'll know that yet another milestone in American politics has been reached just as it has in our past.
My advice is to relocate to the wilderness when we all sense that it's undeniable that we've reached a turning point. It worked both times before.
I don't think even Kucinich has gone that far...