Cahokia - Wikipedia
How many "odd exceptions" does it take? The point of this thread is to show Santorum inarticulate at best and more truthfully, flat out wrong and bigoted. The historic native population is quite able to prove parity with European culture.
Cahokia was long abandoned by this time, so it really would not count here. Similarly, even if it had not been, it would be an exception to prove the rule. Cahokia still was essentially a stone-based technological level; and if we correlate the geographical continental US with Europe (very similar size), even thirty Cahokias would not be equivalent of all the cities and kingdoms from Portugal to Muscovy.
Much of Europe was made of small villages practicing subsistence agriculture at the time of America's "discovery." They would have gladly hunted and gathered, had the Crown allowed peasants on their land. Why do you think they risked so much to cross over to a larger land? Truly, the European commoner (our progenitor) was the more impoverished culture. Or did you assume affinity with royalty?
Europe was largely a market-based economy, not subsistance-based. For instance, much of the midlands of England was given over to sheep for the Flanders textile industry, fed by Hansa supplied Baltic wheat. The entire system was underwritten by large Italian banking families and the countryside supported the various merchant guilds in the towns or leagues like the Hansa. The peasantry largely had to pay rents, taken in cash by this stage, thus needing to produce more than subsistance to pay for this and additional milling fees and the like. The serfs planted what their lord wanted, which was driven by what brought him most ready cash, with the excess being what they lived off. All this meant that most villages and farmers specialised in one or two products with limited market gardening (as transport was still inefficient). Not even mentioning the importation of luxuries like wine (which even a cursory reading of texts, like Shakespeare or Chaucer, would show was drunk at all levels). The whole is quite different from villages in the Americas, with a dynamic partnership between the Towns and the countryside and long-distance trade.
The American Native cannot show parity in material civilisation to Europe. Afterall, it is Europe that came to America and took it over, and not the other way around. A gun vs a spear speaks volumes. This was why they were so ready to trade, as the Europeans brought stuff they did not have nor were capable of producing. Why they risked crossing over was on many different factors, from poverty to religious persecution to simple greed. The natives in America were not so idyllic as people believe, as native wars and famines and the like were just as common, really. The Noble Savage myth is just as racist as the Savage one. It ignores who the people really were, and replaces them with a caricature simply as a foil to comment on the West - it says more about the West than anyone else, and is similar to Orientalism in that way.