IN 2004, FEARING that Republican Gov. Mitt Romney would appoint a fellow Republican to replace Sen. John F. Kerry should he become president, the Democratic-controlled Massachusetts legislature changed the law, mandating a special election. Now, fearing that the push for health-care reform could be weakened by the absence of a 60th Democratic senator, that same legislature wants to change the law again, allowing the governor -- now a Democrat -- to make a quick appointment. With all due respect to the wishes of Sen. Edward M. Kennedy, this isn't how lawmaking is supposed to work. It smacks of political expediency...