Fourth, there must be domestic support in the United States, which is usually obtained by congressional backing. Conducting policy without such support is very difficult in the short term and unsustainable in the long term. The experiences of the Korean, Vietnam and second Iraq wars show that prolonged stalemates sap public support.

Fifth, we should consider unintended consequences. We need to think about how to protect pro-Gaddafi civilians from atrocities at the hands of rebel forces. The action in Libya may tempt the Iranian regime to speed its development of a nuclear weapon, especially when Iranians consider that Gaddafi gave up his nuclear program for closer ties to the West. Rogue states have to remain convinced of our determination to resist nuclear proliferation.

Sixth, and most important, the United States must develop a firm and differentiated understanding of its vital national interests. Not every upheaval in the region has the same origin or remedy. The Arab Spring has the potential to become a great opportunity for the people of the region and the world. Over time, fostering democracy may provide an alternative to Islamic extremism; it may also, in the short term, empower some of its supporters. We need to develop a realistic concept of what is achievable and in what time frame.