Iranians have risen up in several waves of protests since the 1979 Islamic Revolution, all of which have been crushed by security forces loyal to the theocratic government. Iran’s admission that it accidentally shot down a passenger plane last week, killing scores of its own citizens, has infuriated many and sparked scattered street protests. But it remains to be seen whether the plane tragedy will generate large, sustained demonstrations. Even if it does, Iran’s Revolutionary Guard has decades of experience in crushing dissent. It put down a student revolt in 1999 and quashed the so-called Green Movement that emerged a decade later, even after it brought millions to the streets.