You are missing the whole point. But you don't need to feel you are alone in missing it.

You can describe it as two different camps in Bush's foreign policy.
Camp one said, don't involve the UN. The UN is not a useful means of maintaining global security.
Camp two said, involve the UN. This camp said the UN needs to be strengthened. A strong UN is the path of maintaining global security.

Both camps are advocating what is legal. Not only that but both camps are "strengthening" the law- in opposite directions. You making mistake if you think UN = international law. Camp two wants to make UN becoming more equaling international law. Camp one doesn't want the UN equaling international law. International law existed before the US was founded, and certainly existed before the UN. And obviously in terms of international relations there are other groups other than UN.

Powell was and is in camp two- and Kofi Annan of course is in camp two (it's his friggin job to be in camp two:). Bush was probably in camp two, but he did listen to both camps, and most definitely decided to take the path of camp two. His speech to the UN was a confimation of his choice of taking camp two. Blair is definitely in camp two.
I have no idea which camp the French are in. But what the French did do was to weaken camp two's effort. But Powell is still trying to push camp two and you can't say that camp one was strengthened- basically in the end it will probably be said the Bush and Powell made the right choice to side with camp two. And French torpedo simply missed and wasn't that significant- maybe even "healthy".