This article in the Small Wars Journal details what an active military response may be in response to the "Tea Party" seizing the local government of Darlington. http://smallwarsjournal.com/jrnl/art/full-spectrum-operations-in-the-homeland-a-%E2%80%9Cvision%E2%80%9D-of-the-future
Some of the Threepers have their panties in a bunch and say that this is the US Military planning on crushing internal resistance to the over reaching ever encroaching Federal Government. They may be right, however nothing in that article is in fact illegal by our current structure of Posse Comitatus.
If the "Tea Party" did in fact seize a local government by force and set up a proxy government it would in fact be an act of rebellion in which the President would be within his/her right to declare such a state of rebellion and deploy military forces. The ink was barely dry on the Constitution when George Washington took troops west to crush the Whiskey Rebellion. Reconstruction was barely underway when Posse Comitatus was implemented to keep the Southern States from turning into what we made the Philippines and later Japan, a fiefdom run by a General as "military protectorates."
But some folks forget that "Darlington" has happened before. In Athens, and there the elections gave the "revolution" the mandate of the people. Political power does come from the barrel of a gun.