I don't know what will happen in Egypt, but it might be worth re-reading key excerpts of The Declaration of Independence as a reminder...

These are self-selected excerpts from The Declaration of Independence that jump out at me when I read them and think about the change today in Eygpt and last week in Tunisia.  The parts in bold are my emphasis:

""When, in the course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the laws of nature and of nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation...""

""...whenever any form of government becomes destructive to these ends, it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness.""

""...But when a long train of abuses and usurpations, pursuing invariably the same object evinces a design to reduce them under absolute despotism, it is their right, it is their duty, to throw off such government, and to provide new guards for their future security...""