The images from Baghdad Wednesday were indeed remarkable. I don’t think the American people realize the magnitude of the Coalition’s military accomplishments in this campaign. We are now just hitting the three-week mark in the war and U.S. troops have taken up residence in the Iraqi capital. The war has gone extremely well.

But dangers remain. War is fraught with uncertainty. Friction has a nasty way of rearing its head during even the best planned campaigns.

I felt some trepidation as I watched Iraqi civilians mingling with the Marines in Paradise Square. It seemed to me that there was great potential for mischief. I know that the soldiers and Marines remain vigilant. Their commanders have reminded them that this is no time to get complacent. But a gunman or bomber in such a place could wreak havoc among both Americans and Iraqis.

Former Marine Corps Commandant Charles Krulak coined a term that describes what is now going on in Baghdad: the "three-block war." In one block, Marines and soldiers are involved in close combat with a determined enemy. In another next block, they are performing constabulary operations, maintaining order and keeping the peace. In yet a third block, they are conducting humanitarian relief. The soldiers and Marines might have to carry out these functions sequentially, but it is entirely possible that they might have to execute them simultaneously.

We got a sense of three-block simultaneity today. While elements of the 3rd Battalion, 4th Marines were securing Paradise Square, less than a mile away, elements of the 7th Marines were involved in an intense fire fight on the grounds of Baghdad University. This sort of situation is likely to characterize operations in Baghdad for some time.

There is no question that Baghdad is the "center of gravity" of the Baathist regime. That accounts for the focus on reaching the city as soon as possible, or as I have said previously, making sure the main thing remained the main thing.

But there is another nut that remains to be cracked: Tikrit. This city to the north of Baghdad is important because it is Saddam’s hometown. Most of his inner circle are Tikriti. Saddam began his career as a Baath-party hit man in Tikrit. If he is still alive, he may decide to make a final stand among his kinsmen here. The outcome will be the same but it may take some effort to root him and his fellow dead-enders out. The people of Tikrit might not have the same incentives as those of Basra and Baghdad to tip off Coalition forces. We shall see.

Mackubin Thomas Owens is professor of strategy and force planning at the Naval War College in Newport, RI, and an adjunct fellow of the Ashbrook Center. The views expressed here are his own and do not reflect the position of the War College, Navy Department, or Department of Defense.