Joshua A. Tucker asks an interesting question on a Wall Street Journal blog: "How Does Protest Topple A Government?"
With Egypt as the example, he argues that even with streets flooded with protesters, surely the day-to-day business of running the country can continue behind tightly closed doors. His conclusion: some pivotal actor made the calculated decision that "they would be better off with a different government in place."
In the case of Egypt, that actor may have been the military. Tucker then points to another question. What exactly is it that the protest "does to convince these pivotal actors that a change in government is necessary?" He suggests four possibilities:
First, it could be simply the bad public relations that can come with protesters getting beaten or killed while the whole world watches. We might expect that this would in turn making it harder for the country to manage its international relations with other countries (e.g., in Egypt's case, harder to protect its relationship with the U.S. and U.S. military aid).
Second, it could be more of an economic concern. This could be a direct result of the protests, such as protesters actually preventing commercial activity from occurring where they are protesting. Or it could be more of an indirect effect, such as a concern that extended protest will adversely affect industries like tourism. Either way, we could imagine that these pivotal actors would decide that the continued economic cost of the current regime remaining in power had become too high.
Third, it could be a security concern, whereby it comes to seem more likely that security can be maintained by acceding to the protesters' demands than by either allowing the protest to continue or by forcibly suppressing it.
Finally, it might actually be something more normatively pleasing. Perhaps our pivotal actors are willing to let the current regime stay in power as long as they believe the regime has the support of a significant proportion of the population. In the case of non-democratic regimes without real elections, our pivotal actors most of the time are going to be forced to make educated guesses about this level of support. Massive protest may ultimately prove to be a major corrective to these estimates.
That calculus may be much different in a country like Tunisia, Libya or Iran. And you can imagine that each of these points depends on many other factors, and Tucker delves into those in the rest of his post, which you can read in full at WSJ.com.