There are three branches of government, and one of the branches gets to decide who gets to be in one of the other branches.  Via The Denver Post:

In a blow to Colorado Republicans that could affect election outcomes for the next decade, a judge has ruled in favor of a Democratic map that redraws congressional district lines.

In a ruling issued late Thursday, Denver District Judge Robert Hyatt said the “Moreno/South” Democratic map submitted at trial “most accurately reflected and preserved current communities of interest in 2011.”

What does “communities of interest” mean?  Skin color? Accent? Last name derivation?

It’s just institutionalized ethnocentric assumptions based on preconceived notions that people who look or sound alike must think alike.