When Does Rioting Work?

I have had a hard time tearing myself away from CNN to write about business news, so I might as well write about the topic on everyone's mind: when does rioting produce regime change?

I've spent a bit of time over the last six months reading about the rioting in American cities in the late 1960s and early 1970s.  There's no very good theory about why these riots happened--or rather, there are a lot of good theories, but no one that most people seem to recognize as dominant.  Obviously, poverty, racism, unemployment played roles . . . but those things were getting better, not worse, in the 1960s.  And the people who rioted targeted their own neighborhoods, which were often utterly destroyed--the neighborhood where I live is literally still recovering from the commercial devastation of the riots that followed Martin Luther King, Jr's assassination.

But what's really striking about the riots is how little they changed.  They made things much worse in the neighborhoods they devastated, of course.  And they did produce some moderate change at the municipal political level, particularly in DC, where the operations of the city had often been controlled by old-school southern senators whose priorities, to put it mildly, were not the liberty and economic advancement of the city's black residents. But despite what some of the black and white radical leaders of the era thought, there was never even a modest chance that the widespread rioting that followed King's assassination was going to trigger a change in the overall government of the country.  When I compare the trajectory of civil rights before and after the rioting started, it's hard to say that it even really triggered much effective change.

Nor did many protests in many other times and places: Tienanmen Square, or the Green Revolution.  What's the difference? Why do some governments fall, and some stand?

Again, there don't seem to be any very good theories--or rather, the theories that exist are broad and pretty obvious:

1. Rioting from ethnic minorities does not trigger lasting, substantial change.  If the protests in Egypt were led by Egypt's large Coptic minority, it would not be a threat to the regime.  Rioting can change a government, but it cannot make the larger population change their behavior, which is usually what minority groups want.  And when violence starts, the majority group usually closes ranks with the government, even if they were previously sympathetic.
2. The legitimacy of the regime matters. A democratic system, however imperfect, will eventually co-opt protesters, who will always be comparatively disorganized.  Autocratic regimes have better ability to suppress dissent, but less ability to compromise with the outsiders.
3. The moment of truth is almost always what the military does.  This goes back to points one and two.  If the military is willing to fire on protesters, the protesters will lose.  If they aren't, then eventually, the head of the government is going to be told to find himself a plane and get out of the country.
4. Is there an outside power whose opinion the regime cares about?  If so, that power may tell the head of state to take a hike.  We may have done too good a job of isolating Iran and North Korea, here.  Egypt, on the other hand, relies on the US for aid--those are your guns that will be fired at the protesters.  So what the administration is saying to Mubarak in private probably will have some effect.

If Mubarak does fall, what comes after him?  Real, strong democratic institutions?  Or another repressive regime of some description?  Rioting can bring down a government, when the conditions are right.  But it doesn't have a great track record at building good government afterward.