Such a delay thirteen years later is a little different. Health will be less of a problem. The last time around, much was learned about keeping large numbers of troops healthy in a generally unhealthy desert wasteland. The lessons learned comprised hundreds of little tricks and tips that were captured in "lessons learned" documents or memories of many NCOs and officers who were younger soldiers when they were last serving in that part of the world. The time to do more training will be appreciated, and mock ups of urban areas will probably be built to hone street fighting skills. There will be a lot more drills on how to deal with the possible use of chemical or biological weapons.
As for morale, that will depend a lot on what is causing the delay. At the moment, the troops are not too happy about how our erstwhile allies France and Germany are doing all they can to keep the murderous tyrant Saddam in power. Sitting in Kuwait, the troops will have an opportunity to hear first hand from Iraqi exiles; "what we are fighting for." But many of the troops are married and will be away from their families for an extended period. However, this time around, the troops will have access to the Internet and cheap phone calls. So the separation anxiety won't be as severe as it was in 1990. Moreover, at least for the combat troops, extended field duty isn't considered a major negative. Being out in the field, training with their weapons and equipment, is what combat soldiers do. All these guys are volunteers. They know they are headed for combat and realize the more they can train, the better their chances of surviving.
But most of the troops are not in combat units, and for the support troops, the extended stay will be a bit more of a drag. The support units are the ones that build and maintain an elaborate infrastructure that supports the fighters. Morale in these units will take a hit the longer the troops are waiting. Then again, the support troops will constantly be reminded that, when the shooting starts, they won't be right up front shooting back and getting shot at.
It's well to remember that an army is built to operate in the field. In the past, it was more dangerous to be in the field than in barracks because of the diseases and risks of illness from exposure to the elements. But over the last half century, these losses have been sharply reduced. The main thing keeping armies out of the field these days is the expense of it. Bringing food, medicine, water and some of the comforts of home into the field is expensive. It also costs a lot of money to have the troops training all the time out there. A lot more ammo is used and there is more wear and tear on the equipment. But it's "out there" that battles are fought, not back in the barracks. And the longer you can afford to keep the troops practicing under realistic conditions, the more effective they will be.
What happens if, for whatever reason, the U.S. and British troops massing in the Persian Gulf have to wait another six months for an invasion of Iraq? How would this wait affect health, readiness (fighting skills and combat capability) and morale? Actually, we have a model for this. American troops waited from two to six months in the Arabian desert in 1990 before attacking the Iraqi troops in Kuwait. It's generally recognized, from that experience, that there was no adverse effect on the troops health. The time waiting was put to good use training for a war in the desert. As for morale, the heavy training schedule, and anticipation of the upcoming combat, kept everyone's minds off the fact that they were camping out in the middle of a desert.