Actually under the context it was used in, it was perfectly alright to be referenced as "the war". Seeing as it directly involved The U.S. and Britain and that was what they were talking about. Had something like "that's why we had to come in to save you in the war" been said, in that context "the war" would refer to WWII. Context, it's great when trying to get your meaning across.

The more you know!