The link between politics and war will be very apparent when the new transitional Iraqi government begins calling the shots on the streets of Baghdad. The current play of Iraqi politics demands that the Iraqi leadership show its independence from the very occupier that protects its emerging government. This is both good and bad news for American forces in the country.

The good news is that Iraqi security forces will be taking more responsibility for policing Iraq -- as they must, if Iraqis are ever to have any government at all. The bad news, though, is that American forces will now begin the slow, and occasionally frustrating, business of coordinating their operations with an ally -- in this case, a weaker but more assertive ally -- that, paradoxically, both needs American power and must show it is independent of it.

The transition is going to be tough for the soldiers and Marines on the ground, who will no longer have the freedom of action they exercised while the United States was an occupying power. Before, if they saw a target, they could try to hit it. Now, their actions are going to be far more constrained by the need to clear their operations with the host country.

Many U.S. commanders and noncommissioned officers are veterans of negotiations with other armies -- the American experience in Bosnia, Kosovo and elsewhere will pay off as soldiers on both sides in Iraq struggle to overcome language and cultural barriers to effective operations. Overcoming these barriers will be critical in the face of a rising Iraqi and foreign insurgency and as the burden of security begins shifting from America to a legitimate Iraqi government.

The mechanics of that shift on the ground will be delicate. Initially, U.S. forces will retain considerable operational leeway, but as Iraqi authority grows, joint Iraqi-American civil and military planning will increasingly become the order of the day, and U.S. troops will slip more and more into training, support and backup roles for the Iraqi army and police forces.

But since the terrorists' primary goal is to sever the relationship between the Americans and the nascent Iraqi government, we can expect stepped-up attacks on U.S. forces after June 30.

How will U.S. troops respond? Despite the new constraints under which they will operate, the troops will retain the right to respond when attacked without asking anybody's permission. Follow-up operations to track down terrorist cells, corner insurgents in their holes and dig them out will be joint U.S.-Iraqi undertakings, particularly in urban areas. Managing the mix of forces and responses will take political and military savvy on both sides of the alliance.

For American commanders, "support" and "backup" pose some peculiar challenges. U.S. military doctrine emphasizes aggressive, decisive operations -- waiting to be hit is not the American style. So the transition to support and defensive operations, even as the terrorists escalate their attacks, will be a major change.

There will be enough fighting in Iraq for the foreseeable future to keep the troops from going slack, but new techniques and tactics for sharing the combat load will have to be developed -- in fact, are probably being developed now -- and new ways to coordinate political and military efforts at the local and national levels will have to be worked out. It's not going to be easy -- but then, nothing has been in Iraq.

If the new Iraqi army makes a decent showing and local security forces stick to their guns, American soldiers on the ground will undertake more operations in coordination with both groups and fewer that involve purely U.S. patrols and sweeps. This is as it should be. As Iraqi forces become more expert, American forces will be less and less visible in populated areas, and American garrisons may be relocated farther away from towns and cities.

The U.S. forces will provide backup for the Iraqi forces. They'll train with, support and on occasion fight alongside them, but within a political context that will seek to minimize the Americans' contributions. Assuming the Iraqis can handle the job, the shifting U.S. emphasis from independent offensive operations to support of the new nation's own armed forces is good news for both America and for Iraq.

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Robert B. Killebrew is a retired U.S. Army colonel who served in infantry and special forces units and who now writes and speaks on defense issues.