Andrew Exum delineates our dilemma:

[T]he very source of U.S. leverage against the regimes in Bahrain and Egypt is that which links the United States to the abuses of the regime in the first place. So if you want to take a "moral" stand against the abuses of the regime in Bahrain and remove the Fifth Fleet, congratulations! You can feel good about yourself for about 24 hours — or until the time you realize that you have just lost the ability to schedule a same-day meeting with the Crown Prince to press him on the behavior of Bahrain's security forces. Your leverage, such as it was, has just evaporated. The same is true in Egypt. It would feel good, amidst these violent clashes between the Army and protesters, to cut aid to the Egyptian Army. But in doing so, you also reduce your own leverage over the behavior of the Army itself.