http://en.wikipedia.org/wiki/Domestic_terrorism_in_the_United_StatesOr, to run down Wikipedia's list of "key criteria,"
we have: violence; psychological impact and fear; performed for political goals; usually deliberately targeting non-combatants; and unlawfulness. That's terrorism.
Things are bound to get worse because a number of factors have aligned to produce these poor creatures. They are out of political power, they are suffering economically, their propaganda sources have not been shut down, and they are faced with having to admit that the
actual practice of their ideology has ruined them. That last thing will never happen. Instead, they may burrow deeper into delusion and disbelief, or change ideologies, or pop off and start shooting something.
I can think of two immediate and obvious paths which can be taken to reduce this problem.
The first is to figure out a way to stop scaring the hell out of these people. They're very easily frightened. Somehow we need to tune their delusions so that they do not feel so threatened. Send 'em Christmas cards, or maybe figure out a way to reign in the right-wing crank organs. Society will have to intervene by itself if the Constitution prevents the government from doing it.
The other way is, strangely enough, to improve the social safety net so that these people (and a whole lot of others) do not hit rock bottom. That has to include improvements in health care, welfare, unemployment, and, as that jerk Adkisson proved, food stamps.
I'm sure there are plenty of other approaches to take, but that's what I think is important.