This is an update to my earlier post, "Preemption Doctrine Adds Nuclear Option."  The respected White House correspondent, Helen Thomas, turned up the heat under Presidential Spokesman Scott McClellan on the general issue of preemptive war:

Q
Does the President know that he’s in violation of international law
when he advocates preemptive war? The U.N. Charter, Geneva, Nuremberg.
We violate international law when we advocate attacking a country that
did not attack us.

MR.
McCLELLAN: Helen, I would just disagree with your assessment. First of
all, preemption is a longstanding principle of American foreign —

Q It’s not a long-standing principle with us. It’s your principle.

MR. McCLELLAN: Have you asked your question?

Q It’s a violation of international law.

MR.
McCLELLAN: First of all, let me back up, preemption is a longstanding
principle of American foreign policy. It is also part —

Q It’s never been.

MR.
McCLELLAN: It is also part of an inherent right to self-defense. But
what we seek to do is to address issues diplomatically by working with
our friends and allies, and working with regional partners….And it’s important what September 11th taught us —

Q The heavy emphasis of your paper today is war and preemptive war.

MR.
McCLELLAN: Can I finish responding to your question, because I think
it’s important to answer your question. It’s a good question and it’s a
fair question. But first of all, are we supposed to wait until a threat
fully materializes and then respond? September 11th —

Q Under international law you have to be attacked first.

MR.
McCLELLAN: Helen, you’re not letting me respond to your question. You
have the opportunity to ask your question, and I would like to be able
to provide a response so that the American people can hear what our
view is. This is not new in terms of our foreign policy. This has been
a longstanding principle, the question that you bring up. But again,
I’ll put the question back to you. Are we supposed to wait until a
threat fully materializes before we respond —

Q You had no threat from Iraq.

MR. McCLELLAN: September 11th taught us —

Q That was not a threat from Iraq.

MR.
McCLELLAN: — some important lessons. One important lesson it taught us
was that we must confront threats before they fully materialize. That’s
why we are working to address the threats when it comes to nuclear
issues involving Iran and North Korea. That’s why we’re pursuing
diplomatic solutions to those efforts, by working with our friends and
allies, by working with regional partners who understand the stakes
involved and understand the consequences of failing to confront those
threats early, before it’s too late.

Q What are the consequences?

MR. McCLELLAN: The consequences of a nuclear armed Iran, they are very serious in terms of stability —

Q Are you warning Iran that it has consequences as you did Iraq?

MR. McCLELLAN: Well, what has happened with Iran
right now is that the matter has been reported to the United Nations
Security Council because the regime in Iran has failed to come into
compliance with its safeguard obligations, and they continue to engage
in enrichment related activity. And we have supported the efforts of
the Europeans to resolve this matter diplomatically, but the regime in
Iran continues to pursue the wrong course.

They
need to change their behavior. They continue to defy the international
community. That’s why the matter has been reported to the Security
Council. We have now entered a new phase of diplomacy. And there are a
lot of discussions going on about how to prevent the regime from
developing a nuclear weapon capability, or developing nuclear weapons.
And that’s why those discussions are ongoing.

This
is an important issue. It outlines in our national security strategy
that this is one of the most serious challenges that we face.

Q Are we threatening Iran with preemptive war?

MR. McCLELLAN: We’re trying to resolve this in a diplomatic manner by working with our friends and allies.

Was
Helen Thomas’s hair on fire, so to speak?  Wasn’t she
simply in error in stating that preemption has never before been part
of U.S. strategic policy?  Discussing the 2006 WSS, Stephen D. Welsh,
of the Center for Defense Initiatives’ International Security Law
Project, cites Thomas’s line of questioning as evidencing "skittishness."  Welsh had written, giving the backround for the 2002 WSS, that

The most widely accepted modern standard for anticipatory self-defense was
articulated by U.S. Secretary of State Daniel Webster in diplomatic
correspondence with his British counterpart over the Caroline incident … and consisted of two
prongs.  One was that the need to use force in anticipatory self-defense must
first rise to the level of being a necessity, and one that is instant,
overwhelming, and leaving no choice of means and no moment for deliberation. 
The other requirement was that the action taken must be proportionate to the
threat and not be excessive.

So,
pace Thomas, preemption has long been an accepted part of just war
doctrine.  But Welsh’s commentary on the 2006 WSS notes that 

The NSS embraces a concept of preemption that incorporates
a broader calculus more reminiscent of civilian tort law and tactical military
planning, including the scope of harm resulting from a worst-case scenario and
an analysis of risk and generalized threat as a broader concept, as opposed to a
specific decision by a potential adversary to launch an imminent attack.
…
In the context of preemptive war, it is possible the NSS may
be seeking not simply to push boundaries, but to reinterpret the original
standard in the context of current developments and advances in technology. 
Analogous to an activist judge [sic] pushing a “living Constitution” that seeks to
stretch 200-year-old standards to cover modern activities without the benefit of
constitutional amendments, the NSS doctrine may seek to rewrite the old
anticipatory self-defense standard in the following manner. 

The traditional rule, it might be arguing, was not just
that one could call a first-strike an act of self-defense if an enemy was
itself poised to attack, but really meant that one could call a first-strike an
act of self-defense if a potential adversary posed a cognizable threat, and the
first-strike was made at a point in time after which the results of an
enemy attack would be devastating against civilians.  Such a standard, applied
in the Cold War, however, could have produced dangerous results.

Welsh (a master of understatement) nowhere explicitly acknowledges that the 2006 NSS includes nuclear weaponry–apparently for the first time–among the
not-to-be-ruled-out means available under the Bush Administation’s
already dangerously expansive preemption doctrine.  (The way things are tending, everyone’s hair may catch on fire.)

[Correction: Helen Thomas is affiliated with Hearst, not AP, as earlier posted–thanks to Minh Nguyen for setting me straight.]