Legitimate yelps of pain along with klaxons sounding alarms are reverberating throughout the Pentagon. The cause is sequestration and annual cuts of $50 billion for 10 years to defense spending mandated by 2011's Budget Control Act.

While $50 billion a year against an annual budget of $500 billion-600 billion may not seem draconic, the simple business "Rule of 72" shatters that illusion. And the inexplicable legal requirement to take these cuts "evenly," which means equally, compounds the damage and makes rational planning virtually impossible.

The "Rule of 72" means that money invested with an annual return of 7.2 percent doubles every 10 years. At a 10 percent annual increase, principal doubles in 7.2 years.

But what goes up can also go down.

Assuming the sequestration mandated 10 percent annual cuts continue, the defense budget of $600 billion will be halved in 2020 to about $300 billion in current dollars.

To repeat: On the current course, by decade's end, the defense budget will be half the size of today's. And that doesn't include the pernicious effects of inflation and escalating cost increases for people, healthcare, weapons and pensions.

In simplest terms, military power is a function of size, readiness and modernization. For discussion purposes, this column uses the criteria in which future forces will be professional, well-trained and equipped and ready for a range of military missions equivalent to today's.

Of course, many other options exist including retaining larger numbers in service but at lower levels of readiness and modernization. Using a force designed on the above criteria, then today's 1.4 million active duty force would be cut in half to about 700,000 with similar reductions in reserve, guard and civilian numbers.

Further assuming that U.S. forces would still be required to safeguard American interests on a global basis in Europe, Asia, the Middle East and Africa, South Asia and Latin America, a joint force of about 200,000 could be assigned to each coast and include those units deployed abroad.

Deployments would include both rotational and permanently based forces with perhaps 20,000 in Asia, largely in South Korea and Japan; 10,000 in Europe; and possibly 10,000 in the Middle East and South Asia. And this combined force of 400,000 could meet at least two major contingencies.

A third joint force of about 200,000 stationed throughout the continental United States would be in reserve, preparing to deploy or to serve as augmentation capability in the event of crisis.

The remaining forces of about 100,000 would be in a "training and stand down" status, with a 6-9 month period for preparations to return to fully active service.

Clearly, events will determine the size and shape of the need for overseas deployments.

Presumably, the national command plan will be revised to reflect these levels of manning. Northern Command would still have responsibility for North America and Southern Command for Latin America. European and African commands would be merged into Western Command; Pacific Command would be renamed Eastern Command. And Central Command could be disbanded with its responsibilities divided between the new Eastern and Western commands with the dividing line drawn on the eastern borders of Iran with WestCom assuming responsibility for the Arabian Gulf and Caucuses and EastCom Afghanistan and regions east.

Strategies for reconstitution and regeneration of forces and defense industrial capacity are essential to future military capacity and capability. Sustaining a defense intellectual property base must be a new requirement and one that will require substantial effort to put in place. But, absent crises, smaller defense budgets will demand far different solutions and policies to provide the nation with the industrial and intellectual wherewithal to sustain an affordable defense.

The most important challenge however will be ensuring that the capacity of the future force rests in advancing and insinuating knowledge as a core foundation. This can only be done through a process of continuous learning that will require a revolution in the military educational system.

Tactical and technical knowledge is necessary but not sufficient. Specific knowledge and understanding of regions and peoples are as important as knowing how to use guns and missiles.

And, of course, reliance on allies and partners will become more important as the size of the forces are almost likely to contract greatly and not only in the United States.

It is impossible to know what will be the best, the most effective or even the most affordable force design for 2020 and beyond.

One conclusion, however, is clear: The impact of sequestration if unchecked, and irrespective of technological advances to military capability, will be the absolute necessity to impose fundamental change in how military forces are recruited, educated, equipped and used.

It isn't too early to begin thinking through these issues now.

(Harlan Ullman is senior adviser at the Atlantic Council in Washington and chairman of the Killowen Group, which advises leaders of business and government.)

(United Press International's "Outside View" commentaries are written by outside contributors who specialize in a variety of important issues. The views expressed do not necessarily reflect those of United Press International. In the interests of creating an open forum, original submissions are invited.)