(Somewhat rhetorical question to start:)
Why did the U.S. Government enter into treaties - which I feel we should honor, because I don't believe you renege on a deal, unlike a lot of folks, apparently - with American Indians? I don't see why "Kennewick Man", should he turn out to be what people are wishing for, would change one thing about the circumstances under which our government made agreements with the tribes.
It wouldn't - except, as shown above, people are really hoping a slick lawyer could change that.
However, what people continuously fail to mention is one simple fact - The scientists WERE allowed to stufdy the remains after they were found, and EVERY conclusion was of someone who was NOT Caucasian and not a MODERN American Indian - they were of Asian ancestry. Period. End of story.
However, because some stupid clay modelling done that made Kennewick Man look like Patrick Stewart, some people decided it must have been a white guy who was killed by newly-arriving indians blah blah blah...
People can be ignorant about some things, is the bottm line.