Well, one need only do simple mathematics on the outcomes, just within a generation of marrying anyone less than half in blood quantum--in two generations, you would not qualify under this legally putative definition. Or you could read through congressional testimony to see the many examples of this played-out throughout the last 100 years.

From a tribal perspective, in December 16, 2003, a Southwest Tribe made headlines when it announced that 50 Percent Isleta Blood Needed To Stay In Tribe. Dozens of people who spent their whole lives thinking they were members of the Isleta Pueblo are finding out they are not. People on the Pueblo have been getting letters telling them they have to have 50 percent Isleta blood to be part of the tribe. The letters they received say that people can challenge them if they fill out a family tree proving their heritage.