Matt Yglesias has a very smart take on what the Beck-Bachmann-Hannity militia stuff is really about, in their minds:
People who believe in violent revolution and the murder of American soldiers and policemen generally, if on the left, appeal to basically anti-patriotic attitudes. Which is about what you would expect from advocates of the violent overthrow of the established political order. But the militia crowd exhibits much more the attitudes one would expect from a coup leader—a Franco or a Pinochet who’s actually appealing to the concepts of patriotism and nationalism as justification for violent revolution.
I suppose there are some different ways of characterizing the asymmetry, but the underlying issue seems to be that rule by conservatives is integral to the right’s conception of the United States of America. This is part of the rhetoric of the “heartland” and “real America”—a period of political victory by a coalition grounded in the coasts and Greater Chicago is a period in which America has ceased to be herself. Thus Michael Barone:
[T]he Republican Party is the party of people who are considered, by themselves and by others, as normal Americans — Northern white Protestants in the 19th century, married white Christians more recently — while the Democratic Party is the party of the out groups who are in some sense seen, by themselves and by others, as not normal — white Southerners and Catholic immigrants in the 19th century, blacks and white seculars more recently.
Now Barone’s not about to go join a militia. But I think this is the basic mentality. The people on the outs are “normal” and the people running the show are “abnormal.” And while I wouldn’t use that language to describe the difference in the coalition, the basic description is right—most Americans are white and most Americans are Christian, and the Republican Party is overwhelmingly the party of white Christian America while the Democratic Party draws its support from a diverse array of non-white and non-Christian ethnic and sectarian groups. But the authentic America is seen as the white & Christian American, an entity in whose defense one can claim to rebel against the actual United States of America.
To put it simply, in the minds of many wingnuts, a right-wing insurrection would be a restoration. This probably explains why the right is generally more interested in the idea of armed insurrection than the left is (at least in the United States).