It is possible that McGaa is a Republican plant, I rather doubt it. The Greens are the ones at fault for him being endorsed, no one else, according to all the stories I've read, which now includes articles in The Nation, The Progressive, and several others.

McGaa published several rather opportunistic New Age books, purportedly about "Native American Spirituality" which have been pretty roundly condemned by Lakota cultural activists, and he is often referred to as a medicine show Indian by many of them. McGaa also doesn't support the Green Party platform, which makes it all the more odd that this guy, who apparently was a complete unknown to the majority of people who voted for him, was endorsed.

I came across this Mother Jones article about him from the Feb 2001 issue on-line while I was trying to find out more about the race. The article is titled "The Seduction of Paul Wellstone":

http://www.motherjones.com/mother_jones/JF01/powerplays_wellstone.html

It doesn't paint a very flattering picture of him either.

As to Wellstone, from everything I've read about this race, it appears there is a deep anger about the way he has sold out his progressive values to become a Washington insider, and not just in Minnesota.