AI Logic Question

[ScottWAR]

In my last game I was Japan, the allies attacked Home Islands with a huge force. I had very few ships there, and was defending with around the same number of aircraft that were attacking. The allies withdrew after 1 round of combat in which they damaged a few of my ships and I damaged a few of theirs. No damage to the base, so I didnt have to send a patrol back. It was a real waste of ships. I had the sea lanes cut off, yet they used their ships for the above attack instead of getting the sea lanes opened back up.