"Private organizations sometimes presume that they can exclude whomever they want, no questions asked."

In light of Sonia Sotomayer's recent club resignation, the WSJ's Nathan Koppel looks at the state of restricted clubs and how courts view their right to discriminate.

And in one sense, they are right. Ironically, the more selective a club is, the more it is considered to be truly private and thus protected against antidiscrimination laws. In other words, a small, all-male group of stamp collectors who meet in a private home aren't unlawfully discriminating by not accepting women.

But clubs that presume they are private frequently turn out not to be in the eyes of the law in some states.

"Over the last 20 years, societal pressures have led to a steady narrowing of what qualifies as a private organization, free from antidiscrimination laws," says Robert Duston, a Washington attorney who specializes in defending discrimination cases.