the Saudis invited us there - the Saudi government represents nobody but itself, a family not unlike a Mafia family. About as representative as the Taliban, and pretty similar in a lot of ways - except a lot wealthier. And as I understand it the reason they have asked the Americans to stay is to protect them against the rest of the Saudi population.
And the only reason Saddam had such a big powerful army was largely because the USA been helped built it up to fight Iran. And, for the British and the French arms dealers and their political subordinates, he was a great customer.
The basis of this thing is the old belief that "my enemy's enemy is my friend", and it looks as if, beneath the rhetoric of fighting for freedom and against terrorism, that is still the underlying assumption.