<It is impossible to justify any such double standard under international law.
International law seems fluid at best. If you're not talking fishing rights or airspace, it's kinda murky, isn't it? The big issues do not seem well delineated, but then I'm not a lawyer.

Might does not make right.
No argument. I haven't heard anyone say it does.

America cannot write its own rules for the modern world.
Yes it can. America is in a unique position in world history. I think maybe what he meant to say was "America shouldn't write its own rules...," which is another issue, one which escapes absolutes, I think.

To attempt to do so would be unilateralism run amok.
What about a nation which is specifically banned, by the UN, from acquiring WMD but which continues to do so? Is that not "unilateralism run amok?" If one nation then decides to enforce UN resolutions, is that unilateralism?

It would antagonize our closest allies, whose support we need to fight terrorism, prevent global warming, and deal with many other dangers that affect all nations and require international cooperation.
Which of our major allies would be antagonized by the removal of Hussein? Which of our major allies beleives that we'll turn Iraq into a slave state? Who beleives that Iraqis will have a more difficult life with Hussein gone?

It would deprive America of the moral legitimacy necessary to promote our values abroad.
Do non-Americans really assess US "moral legitimacy" before either accepting or rejecting American values? My guess is that television and music have a greater impact on how America is perceived in most of the world. The questions "what brings prosperity" and "what brings freedom" are probably more pressing issues as well.

And it would give other nations -- from Russia to India to Pakistan -- an excuse to violate fundamental principles of civilized international behavior.
If they wanted an excuse they'd find or manufacture one anyway, just like they always have. The American government isn't responsible for the activities of Russia or India or Pakistan. Are they countries or are they counties?

The Administration's doctrine is a call for 21st century American imperialism that no other nation can or should accept. It is the antithesis of all that America has worked so hard to achieve in international relations since the end of World War II.
This one is genuinely troubling. The Bush Doctrine is something of a break with the past, no doubt about it. The question, to which I certainly don't have the answer, is: are we abandoning our past too quickly? Are we abandoning a vision of international cooperation and equality which we inherited from those who lived before?

Or, is it a vision which we can no longer afford to pursue? Is it a dream from which we now must awake, for our own safety?

I don't know.