On its own, the US has the firepower pound for pound, plane for plane, missile for missile, to overwhelm the Iraqi armed forces.
However, wars are not won on a comparative count of military materiel. US military superiority would make a one-off military strike very easy. But to launch a successful large-scale campaign against Iraq the US will need air bases on land in the Gulf region, and for this it must persuade Gulf states to support its proposed action. Politically it needs at least the acquiescence of its NATO allies and probably of Russia before striking against President Saddam Hussein. This weekend as the US Secretary of State continues to tour Europe en route to the Middle East, such acquiescence is still not certain. French opposition to a military strike appears to have weakened somewhat, but Russia is still opposed.
The military build-up continues regardless. There are now 24 US naval vessels in the Gulf - 13 are combat ships and the other 11 are support vessels. Two are aircraft carriers - the USS George Washington and USS Nimitz - each carrying 70 fighter/bomber aircraft. The George Washington alone carries five million pounds of bombs, and the Nimitz is of similar size.
Six other vessels are capable of firing Tomahawk missiles at Iraqi targets. A third aircraft carrier, the USS Independence, will arrive in the Gulf within a fortnight to replace the Nimitz.
Altogether the US has 325 aircraft in the Gulf region, including those on board the aircraft carriers and those in land bases in Gulf states. Meanwhile, the British aircraft carrier, HMS Invincible, with 15 fighter-bombers arrived in the Gulf from the Mediterranean last week. A British destroyer, HMS Nottingham, and a frigate, HMS Coventry, are already in the Gulf as part of routine patrolling.
Should France come around to agreeing to become involved again in a coalition against Iraq, it would be expected to send aircraft, but not aircraft carriers. The French Foreign Minister, Mr Hubert Vedrine, said on Thursday that all options were open in relation to Iraq. This is seen as a softening of France's opposition to a military attack.
The key to whether a military conflict takes place, and what shape it will take appears now to depend on the visit of the US Secretary of State, Ms Madeleine Albright, to the Middle East.
To maintain an onslaught on Iraq, the US needs the use of land bases in the region. While the aircraft carriers bring huge firepower, ultimately they can run out of ammunition. Permission to use land bases in Saudi Arabia, Kuwait or Bahrain would open up the prospect of almost unlimited aerial firepower being deployed in the Gulf.
Ms Albright's visit to the Gulf this weekend is designed to shore up the support of Iraq's neighbours for the US stance against President Saddam, thus giving the US the option of using their territory as a land base for a major onslaught. The US already has a naval base in Bahrain and large military installations in Saudi Arabia and Kuwait, but would need at least the acquiescence of the host states before using these facilities for a sustained attack.
The Turkish Deputy Prime Minister, Mr Bulent Ecevit, yesterday ruled out the prospect of the US using its bases in his country for an attack on Iraq.
The 120 fighter/ground attack aircraft in US bases in Italy, Germany and Britain could be deployed to a land base in the Gulf within hours. Enormous numbers of additional aircraft could come from the US very quickly.
President Saddam's air force appears utterly incapable of dealing with such opposition, according to Mr Tim Trevan of the London-based International Institute for Strategic Studies. Iraq has some 250 operational aircraft, and these have weapons and avionics systems considerably inferior to those of the US planes.
"If the Iraqi air force takes to the air it will be shot down," he says. "It will be a turkey shoot."
The other options open to Iraq are a land war or the use of missile-driven chemical or biological weapons. In the case of the former, military observers believe that the US would not even need ground troops to thwart President Saddam. Daily satellite and air surveillance of Iraq would pick up any significant troop movement. Aerial bombardment would be enough to end any mass mobilisation.
Even if President Saddam's troops did get to the borders of Saudi Arabia or Kuwait, the defences of those countries have been much strengthened since 1991, while the Iraqi army capability appears to have diminished.
Most Iraqi army brigades, even the elite Republican Guard, are understaffed and under-equipped and the quality of the troops available is said to be low. "Do they love Saddam?" asks Mr Trevan. "Are they willing to die for his regime? There is a hard core in the Republican Guard who will fight hard as their interests are tied in with the survival of the regime, but there are not enough."
The other option - the unleashing of anthrax or botulism spores or poison gas on densely-populated areas - is the most fearful prospect. However, it is not clear that Iraq has a substantial number of missiles with which to propel these deadly products to their targets.
Nor is it clear who he would unleash them against. "If he uses them against Israel, Israel's response is that Iraq gets nuked so that's not going to happen," according to Mr Trevan.
Using them against anyone else, such as Gulf states co-operating with the US or against US troops, would bring down the wrath of the entire international community, he maintains, ending any opposition to an all-out attack and thus ensuring President Saddam's downfall.
A calculation that he therefore would not use these weapons appears logical. The problem is whether it is safe to predict what President Saddam would do if he were reduced to that last option.
