There is a great discussion about what the role of libertarianism and war should be. I highly recommend it and the comments to see that there are many thoughtful people out there who are looking into this issue.
One of the fun things about being an adult is dealing with moral dilemnas. This is just one example. Another question for the Volokh Conspiracy might be what is the propler libertarian stance on abortion. On the one hand, you don't want the State to dictate what people should do. On the other hand, do we not need to protect all people in order to allow them to make reasoned and informed opinions?
What fun, especially when good and moral people can come down squarely opposite one another on the issue.