Instead of discussing the technical characteristics of the survey, it would be better to check if those numbers make sense.
In any country, whenever there is a war, if that war is considered as a fair and just war, population will be in favor.
wetter the regime they live in is a democracy or a dictatorship, they will rally behind their leaders.
Therefore, the result of the survey makes sense.
750 individuals can be enough if the organization that carried out the study, believes that those 750 persons are representative of the whole population.
Of course, poles, surveys and the likes can be subject to error, when the chosen universe is not correctly chosen.
But the fact is:
the surveys in the US and the UK are effectively favorable to the war.
We should try to understand why, instead of discussing the surveys, because there is one very basic thing about surveys we all should know about. They can't be ALL
The US public opinion is favorable to war because the US administration lied to the public. They have created the idea of a very short two or three days war (this was hinted not explicitly said, because the people at the Pentagon clearly knew much more than they were willing to say).
Having made their case, the war could start, as it did, because the public opinion was now in favor.
After having started the war, the problems start to appear. (I don't believe the strategists at the Pentagon didn't had a hint about how the Iraqis would fight).
Now, with some American victims and with a population enraged by the pictures of US P.O.W's (even better if you give the impression that some of the deaths took place later - means: killed). The US population is prepared to continue support for war.
We must try to understand the reasons why the public opinion actually reasons like it reasons.
The US administration has been extremely successful in selling their product (War on Iraq).
The Pentagon marketed the war, like any big company would have done to guarantee good sales to some soap, deodorant or pizza.
The surveys are just showing they (Pentagon and Dep. of Defense) worked well, the marketing was good, advertisement was even better and the product is selling like hell.
We may not like those people, but we must recognize they were astonishingly smart. (Unlike Saddam and his idiotic advisors. The Iraqi minister of information is a pitiful image of idiotic propaganda)