The WSJ has a useful piece up right now revealing that the real threat behind all of this Middle East unrest is: Iran. And not only is the real threat Iran, but the government’s entire policy was shaped to stop Iran from doing Iranian things.
The worry, I suppose, is that Shi’a will take over governments in the Middle East, and will therefore be predisposed towards the Iranian point of view. I don’t think the view does as much work as the sources behind the article want it to do: Shi’a are not monolithic; Iranian influence in Iraq, for example, has not exactly been comprehensive and will probably continue that way even in the absence of the U.S. (Ayatollah al-Sistani, for example, is not particularly aligned with the Iranian government); and, of course, the revolutions have been mostly secular in character. The revolutions might make the Iranian government relatively stronger vis-à-vis its Middle Eastern rivals, but it seems unlikely that they would gain strength absolutely.
If I might be cynical: this strikes me as an attempt to plant the idea that there are important, wider strategic interests at play in the Libya intervention—namely, the continued encirclement of Iran.