Left and right accuse each other of hypocrisy on foreign policy, shock!

I'm not sure what you mean when you say that both left and right are against War (?war). Obviously that's true in one sense, in the same way that everyone is in favour of love, against rotten tomatoes, etc. But in another sense it's not true. Most people, on both left and right, believe, and always have believed, that the possibility of war should be considered in certain extreme circumstances - in particular, when there is a credible perceived threat to themselves or their essential interests.