London

Beware the sledgehammer used to crack the nut. In this case, the nut is the U.S. government's laudable goal of catching tax evaders. The sledgehammer is the overreaching effect of legislation that is alienating other countries and resulting in millions of U.S. citizens abroad being forced to either painfully reconsider their nationality, or face a lifetime of onerous bureaucracy, expense and privacy invasion.

The...