Opposing war and at the same time knowing that reality sometimes requires it are not inconsistent positions.
I oppose killing people in general, but would kill an intruder in my home without a moments regret to save my family.
The other question (which the question of this thread begs) is, can you support our troops but oppose a specific war?
I support our troops, I support this war. I supported our troops in Yugoslavia but opposed that war. If you can't, oh well.
Dittoes.