The Pentagon is considering a realignment of US forces - with far-reaching implications.
"We're aiming to achieve the most basic and comprehensive review of the nation's global defence posture since the United States became a world power," said the Under-Secretary of Defence for Policy, Douglas Feith, in a speech in Washington this week.
The Iraq war showed the need for mobility and flexibility
It was a bold claim from the Pentagon's number three.
Mr Feith and Under-Secretary of State Marc Grossman are heading for Europe next week for talks with more than a dozen countries about the Pentagon's plans.
Visits to other regions will follow.
Pentagon officials insist that no decisions have been reached, that the talks will be real consultations and that the results of the review will unfold only over several years.
It is not, Mr Feith insisted this week, a short-term effort to free up troops for Iraq.
Cold War hangover
The Bush administration came to office espousing a policy of transforming the US military to make it more flexible, more agile and better able to meet current and future threats.
Part of that included looking at US force levels around the world, which the likes of the US Defence Secretary, Donald Rumsfeld, see as still very much hangovers of the Cold War.
Many of the forces are still configured chiefly to fight "in place", whereas what the Pentagon is now looking for is forces that can deploy rapidly, to "project power" in the jargon, to wherever a crisis might develop.
The administration will have to convince not only America's allies but the US Congress as well
The review clearly took on greater urgency after the attacks of 11 September 2001 and the conflict with Iraq.
It could mean fewer forces stationed in certain countries, a greater reliance on simply having prepositioned equipment in place and more emphasis on rotating troops into and out of certain regions for short periods.
Clearly, all this has major potential implications for countries like Germany, Japan and South Korea, where there are significant numbers of troops based now, as well as other countries where the United States might seek new bases or at least new access agreements and new forms of military ties.
These could be in Central Europe, Central Asia, and perhaps also Africa.
In South Korea the US plans to withdraw troops from the border
But it is all very sensitive, which is one reason why no one in the Pentagon is ready to talk in public at the moment about numbers of troops or particular bases.
Still, as Douglas Feith put it, "it would be a remarkable coincidence when this process is over if we have the same number of forces abroad and the same number of forces at home".
The Bush administration is clearly anxious to avoid suspicions that, with this review, it is really in the business of retrenchment, isolationism and unilateralism.
So part of the mission of Messrs Feith and Grossman will be diplomatic reassurance that the United States is not about to abandon key alliances.
At the same time, Washington clearly sees the review as an opportunity to try to reduce some of the frictions which the presence of sizeable US forces has caused in some countries, like Japan and South Korea.
Although not strictly part of the review, the withdrawal of the US Air Force presence in Saudi Arabia after the end of the main conflict in Iraq is seen by the Bush administration as a potential benefit to US-Saudi relations.
Currently there are about 75,000 US military personnel in Germany, 40,000 in Japan and 37,000 in South Korea.
Although US officials will not admit it, the clear implication of their plans is that troop numbers in Germany and Japan could fall quite substantially.
At the very least US troops in South Korea will be redeployed away from the Demilitarized Zone, and many of the current US bases around the world could close or be substantially reduced.
But, as part of its public relations offensive, the Pentagon is arguing that the advances in military technology displayed in Afghanistan and Iraq show that troop numbers are no longer a reliable measure of military capabilities, so that even if those numbers fall in some regions, that will not necessarily mean any reduction in military capabilities.
The aim, officials insist, is to strengthen alliances with more capable US forces, even if they may be less numerous.
All that may be very well. Clearly there is a lot of work ahead.
The administration will have to convince not only America's allies but the US Congress as well.
And another thing Mr Feith conceded is that the Pentagon has no real concept of what the ultimate net cost of all these upheavals might be.