I'll let him address whether there's a natural leader.
I will say, though, that it's more than students who are looking for change. We also see that people who are looking for change are not looking to overthrow the government; they're looking for change within the government structure right now.
Again, we don't know the details, but there is definitely a power struggle going on within the clerical establishment. Much of that is based on old grievances and fights that have happened over the last 30, 40 years. One reason it may be escalating is that Khameini is apparently unwell.