The US has ordered the headquarters for the V (fifth) Army Corps and the 1st Marine Expeditionary Force to Kuwait. 

There are sufficient American forces in Kuwait and the Persian Gulf to launch an attack on Iraq. This would be the "light and fast" attack. But the number of troops on hand is also sufficient to rush to Baghdad if there is a successful coup. Overthrowing Saddam could trigger a civil war in Iraq, and the U.S. would need to get into Iraq with troops as soon as possible to prevent chaos. 

The U.S. army already has two armored brigades operating in Kuwait. One marine brigade is also there, and another just arrived off shore. Several more brigades worth of army equipment are on their way to Kuwait. An Apache helicopter gunship battalion has just arrived and two aircraft carrier task forces are in the Persian Gulf. There are over a thousand Special Forces and commando troops in the region. 

The U.S. air force has established half a dozen air bases up and down the Persian Gulf. Moreover, it is understood that at least one major Saudi air base would be available for American operations against Iraq. The U.S. air force has purchased large quantities of aviation fuel and brought in lots of support equipment, which would make it possible for up to a thousand warplanes to operate. The aircraft could be flown in within days.