The Wall Street Journal tells the tale.

Washington, DC has an 8.5% unemployment rate, and it has come up with an ingenious plan to keep it high: the city council voted 8-5 late last month to require a $12.50 an hour “living wage” for certain big retailers, well above the current national minimum of $7.25.

The wage floor applies to stores with 75,000 square feet of space and $1 billion in parent-company revenues….

[T]he proposed law exempts companies operating under collective-bargaining agreements.  …supermarket chains like Safeway and Giant get a pass because they have union workforces.  So paying a non-living wage is fine as long as it also finances union dues.

Meanwhile, the unions keep jobs scarce and available only to union members.  And union power intact.

Hmm….