It's not terribly surprising that the racist arm of the Republican Party have resorted to Brown Shirt thuggery. Last night was a sort of mini- Kristallnacht where tea party Republicans threw bricks at Democratic windows.
While it is true they can't match the Nazis, yet, and are mostly pathetic vandals, it is not for lack of desire.
Being thugs they are afraid of public gaze. Hence the bricks thrown in the dark. Being extremists they can think only in terms of destruction and murder. Hence the death threats. Being fanatics they believe everyone who is not one of them (the majority of the country) are demonic.
They are not dangerous. Yet. They are not dangerous because they are a disorganized band of bullies. They can become dangerous if a state government, think Texas, formally sanctions them.
Embryonic Brown Shirts
The Original Kristallnacht