When people are allowed to choose the race they belong to, they will naturally make the choose they think offers the most benefits!

Hence, unqualified, lily-white Elizabeth Warren gets a job on the Harvard faculty by asserting she's a Cherokee Indian!

In times and places where "one drop" of black blood keeps you out of college, a mulatto will claim to be white. When "one drop" will get him a scholarship, he decides he's black.

Simple.