Once demonstrations get to a certain size, or the government is unwilling to cause too much bloodshed protests can topple a government. The overthrow of the Shah demonstrated this, as did the rolling back of communism in 1989. Unfortunately it is very difficult to measure when or if the protesters will gain the upper hand or the willingness of the authorities to be brutal in putting down protests. It may depend partially on how big the change would be; in this case the tipping point may be quite low as the likely change in regime is simply from the more radical elements to more moderate elements within the current elite rather than a full scale revolution. Is the tipping point nearing?