There are four possible explanations for such an increase.

The first is that U.S. ground forces are not large enough to support the war in Iraq, especially with the president's decision to send 21,000 more troops there. It is now clear that the United States did not send enough ground forces to secure Iraq after the 2003 invasion.

However, the U.S. Army and Marines cannot be expanded rapidly without sacrificing their quality, which the generals will not and should not allow. Therefore, the only way a bigger Army and Marine Corps could affect Iraq is if that war drags on for years to come at the current or higher level of U.S. forces. If that is the rationale for the expansion, the American people and their elected representatives will likely balk.

A second possible justification for expanding U.S ground forces is the need to recover from Iraq. Clearly, the Army and Marine Corps have been weakened by a war that has gone on longer and taken a higher toll on those forces than anticipated. Apart from Iraq, their strength must be restored for the sake of U.S. global security interests.

But while the need to undo the damage to U.S. ground forces from Iraq is undeniable, it does not follow that the way to do this is to expand. The priority should be on rebuilding their quality, readiness, and morale, not their numbers.

The third explanation for enlarging the Army and Marines -- the one that Gates actually cites -- is that more ground forces are needed for the "global war on terror."

This presupposes that U.S. ground forces are a critical instrument with which to counter the jihadist insurgency in the Muslim world and/or prevent strikes similar to those of Sept. 11, 2001, against the United States. But if the years since Sept. 11, 2001, tell us anything, it is that invading Muslim countries is unproductive. Is the administration saying, in effect, that it did not have enough ground forces for Iraq but will the next time it occupies a Muslim country?

The very idea that the United States can protect itself by fighting ground wars in the Muslim world has surely been discredited by what has happened in Iraq (regardless of what America does there now). Many Muslims buy al-Qaida's argument that jihad is justified precisely because Islam is under attack by the United States.

Consequently, fighting ground wars in the Muslim world appears to enflame, not quell, Islamic terrorism (as the CIA has recently affirmed). In Iraq, for example, while U.S. forces have killed or detained more than 70,000 insurgents, the size of the insurgency has grown from 5,000 to 30,000. Under such conditions, the United States would need to send millions of ground troops to the Muslim world, not a mere 93,000 more.

If expanding the Army and Marines is all about the global war on terror, the United States could get a much greater payoff from investing $10 billion in building indigenous police, courts, schools, job-training centers, and health clinics -- things that give Muslim populations reason to support their governments and reject the jihadists. But since Sept. 11, 2001, the resources that have gone into such important capabilities are a pittance compared with the increase in U.S. spending on military forces, most of which is irrelevant to this enemy.

To the extent that U.S. military capabilities need to be improved to counter terrorists, the investment should be in special operations forces and homeland defense, not land armies.

A fourth possible rationale for expanding the size of U.S. ground forces is that they are needed not for Iraq or the global war on terror in general, but instead to counter other threats. While the Bush administration has not offered this explanation, logical completeness requires that it be examined if none of the first three explanations wash.

The problem with this idea is that large ground forces are not relevant to any of the other threats on the horizon -- Iran, North Korea and, less likely, China. Rather, U.S. plans to counter these dangers rely mainly on air, naval and missile-defense forces.

Thus, to the extent American leaders are concerned about these threats, which have gotten short shrift since the Iraq war began, they should think twice before reducing investment in the forces needed to deal with these threats in order to pay the bill for larger ground forces.

This is not to say that a case cannot be made that the United States needs more ground forces. Rather, it is to say that it has not.

(David C. Gompert is a senior fellow at the RAND Corp. a nonprofit research organization. He served as senior adviser for national security and defense for the Coalition Provisional Authority in Iraq in 2003 and 2004.)

(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.)

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