Why should it be non-partisan? National defence involves planning, long range strategy, short term tactics. It is not a button you push. It is a game like chess, and not all players are equally skilled.
Even if democrats could be assumed to be patriotic, they do not play the game the same way, or with the same level of skill. I mean, assuming that John Kerry is an honest patriot, would you want him as Commander-In-Chief?
Do you really believe that skill, experience and tradition count for nothing in national defence?
And if we don’t try to make defense non-partisan, we can get screwed in the future. In the lead-up to World War II, the Republicans in Congress refused to believe that we needed to build our military. The result was that in the aftermath of Pearl Harbor, we were totally unprepared. That is when the GOP, adopted the policy of “politics stops at the border.” And we have kept it ever since.