These principles affirm the inherent right of states to use force in individual or collective self-defense against armed attack.

Japan's formal position is that the Constitution bars it from exercising the right of "collective self-defense."

To be sure, the debates for now in Japan are likely to focus not on issues of developing nuclear weapons or even on collective self-defense.

Another necessary change might be a redefinition of Japan's concept of collective self-defense.

Article 51 recognizes members' right to "individual or collective self-defense" while waiting for Security Council action.

But it wants to exclude disputes related to national security, including those arising from armed conflicts, individual or collective self-defense or resistance to aggression.

It will be resisted by all appropriate means, including military cooperation in the collective self-defense of the democracies.

-- Allow Japan to participate in collective self-defense.

"The lack of consensus on collective self-defense is an obstacle," Mr. Armitage said.

And the lack of an ability to participate in collective self-defense, although they are signatories to a defense treaty, is an obstacle.