Apparently, we don't need it, or at least not a formal declaration of it, to try our enlightened Mariner (as in from Marin County) for treason, at least if Mark Levin's analysis is correct.

On his reading of the Constitution (which makes sense to me):

The issue, therefore, is not whether the U.S. has declared war, but whether Walker has waged war against the U.S., or whether he has given aid and comfort to the enemy.

The whole analysis is worth a read.

[Update]

I just want to add that I have little to add in the blogger pile on of Mr. Walker. They've already beaten me to all the worthwhile things to say, and James Lileks' latest rant should be the last word. Of course, it won't be, because the so-called professional pundits will continue to say mind-bogglingly stupid things about it.