What's a superpower to do? How to back other people's democratic aspirations when their repressive leaders are such reliable allies?
Some U.S. and Arab strategists are saying that the United States could end up in its weakest position in the region in half a century.
Beyond Tunisia, Egypt and Yemen, U.S. allies including Jordan, the Gulf emirates and Saudi Arabia are seen as vulnerable to political agitation.
And one line of thinking goes that they could pull away from the United States out of the belief that Egyptian President Mubarak's close ties to Washington are a main reason he's so unpopular.