America is a country with a constitution but made of scores of ethnic groups, Irish, German, Russian, African and Hispanic e.t.c. They are all Americans and also have ethnic roots in their respective homelands.
So, yes, it seems out of order to call Americans less educated than Europeans since, hold on a bit..... What about Muhammad Ali? He's an intelligent man with a peaceful outlook but a self-confessed American. Totally different than Bush, I would say, as is Lance Armstrong who is hardly dumb or retarded.
How about America's technological elite - they've been ahead of Europe for decades.
No, Americans aren't dumb at all. What we do see is a large population of Americans who lag behind somewhat and don't maybe go to particularly good schools which may be why Americans are stereotyped. In fact I saw one article in a paper over here that sterotyped Americans as being so rotund they had to be loaded into wheelchairs by a crane. But they're not all fat - Colorado is the slimmest state apparently.
Now Madonna she had a good education in the U.S. and she'll tell you she prefers L.A. and New York to London. It was in a U.S. school where Madonna learned to dance properly and got involved in the arts. Hers was a damned good middle-class school, possibly in Michigan not some dive in the suburbs.