"Unless you were one of the first Americans, a Native American, you came from someplace else, somebody brought you," President Barack Obama told the assembled throngs in Las Vegas on Tuesday.

Perhaps to make sense of the empty phrase "Native American," Obama seems to have overlooked the most contentious debate in modern archaeology: when did the first waves of humanity reach the Americas and where did they come from?  

The only real consensus among archaeologists is that everyone in America came from "someplace else."  Or as the Bill Murray character memorably said in Stripes, "We're Americans, with a capital 'A', huh? You know what that means? Do ya? That means that our forefathers were kicked out of every decent country in the world."

For years, the "Clovis First" hypothesis held sway in the academy.  This school argued that the so-called Clovis people (they didn't call themselves that) crossed the land bridge from Siberia to Alaska during the most recent ice age about 12,00 years ago.  These Siberian-Americans then made their way south through an ice-free corridor east of the Canadian Rockies.

The discovery of the Monte Verde site in Chile in 1975-and other sites in North America-has raised the possibility that some cohort of Asian-Americans arrived on the west coasts of the Americas thousands of years before the Canadian corridor opened.  No one seems quite sure where these people came from, but "Mexico" is not among the accepted hypotheses.

Then, of course, there is the mystery of the Kennewick Man.  In 1996, along the banks of the Kennewick River in Washington, some locals stumbled on the skull of an ancient inhabitant of the area.  On first blush, Kennewick Man appeared to be Caucasoid, a.k.a. white.  In fact, he was said to look like Patrick Stewart of Star Trek fame.

Understanding the financial consequences if Welshmen were re-anointed "native Americans," local Indian tribes and their allies promptly sued to take control of the body.   Only after years of litigation was an anthropologist allowed to examine the remains.  He concluded that the Kennewick Man was likely a descendant of the Caucasoid-appearing Ainu people of northeast Asia.  One senses a bit of politics in that ruling.

This all raises the question: if we can figure out where the 9,000 year-old Kennewick River man came from, why can't we figure out where Obama did?