I wrote up my one experience with the Alliance Navy in a previous post, where I ended up asking a number of the sailors I encountered, "Who is your enemy?" No one could answer that question. They had guns, they were told to guard the base, but they didn't know who to guard against. They ended up not being able to keep out a bored escort, I didn't think they would be successful against a determined enemy, especially if the enemy showed up in camoflage mini-skirts.
Recently the Second Life Herald posted that the Alliance Navy is in a war! Finally, my question was answered.
As reported earlier, attempts by Herald correspondent Urizenus Sklar to mediate peace talks failed recently and the Alliance Navy, one of the oldest military organizations in SL, and the Merczateers, a former ally of the Alliance Navy, began open warfare for the oldest causes of war in human history; land and pride.
A few months ago, the Alliance Navy and the Merczateers were allies. As with any organizations that compete in the same arena, there was a certain amount of competition between the two but in general they shared the same goals and operated as well as any alliance can.
So, the answer is that they fight with their erstwhile allies! The drama demonstrated in the comments to that article, is amusing. The guys, who are supposedly the stable, non-emotional and logical ones, are having a cat fight over hurt feelings and who stole who's knife. Evidently the admirals and generals are having a hissy-cow over some minor thing and started a war over it. And people say I can be moody and vindictive.
If you substitute 'curling iron' or 'boyfriend' into this, you could have any old drama I'm used to seeing. The difference is that when someone steals my boyfriend, I do passive aggressive things like destroying their reputation by spreading the rumor that they are a slut. The guys, not to be out-done, do overtly aggressive things like launching a war and destroying property. Isn't there such a thing as "proportional response"?