Regarding “Wal-Mart: D.C. wage bill a bait-and-switch tactic” [Metro, July 7]:

The members of the D.C. Council who are lawyers, including the Ward 3 member who is a law school professor, should certainly be aware that the anti-Wal-Mart bill is of doubtful legality. Its exemption of union-organized retailers appears to run afoul of the National Labor Relations Act’s preemption doctrine. Congress’s regulation of labor relations in this country is exclusive, and state or local governments are precluded from regulating conduct that is arguably protected or prohibited by federal law. Subjecting employers to different standards based on their unionized status would violate that principle.

Ronald Natalie, Washington