Many people will dismiss the "Oath Takers" as harmless kooks, while others may regard them as patriotic Americans who are expressing their genuine concern for our Constitutional system. Perhaps it would be useful to examine the record of similar groups which have operated in the past.
In the early 1990s, an organization which called itself "The Cross, the Sword, and the Arm of the Lord" held that the Clinton administration posed an immediate threat to the Constitutional freedoms exercised by American citizens. Like the "Oath Takers," they recruited heavily among active duty military personnel. Like the "Oath Takers" they required that new members subscribe to an "oath" to defend the Constitution and oppose, by force if necessary, any and all attempts to "infringe" upon those freedoms. Their particular "enemies" were the FBI, ATF, and the IRS, but they regarded ALL government agencies as evil instruments of illegitimate power.
For the most part, the CSA stayed underground, but on one momentous occasion a member drew national attention.
Timothy McVeigh, who had joined the CSA while still on active duty, and who had attended at least two CSA "camps" (one in Arkansas, one in eastern Oklahoma) was driven by his hatred of all things associated with government to act--and the bomb he created killed 168 innocent people at the Murrah Federal Building in Oklahoma City.
It is not safe to dismiss these people as a "harmless fringe." Such people can become very dangerous--and very destructive--without warning. One of the best sources for information on groups like this is Morris Dees' Southern Poverty Law Center, who keep track of these guys and provide information about them on the SPLC website.