In March, the Supreme Court's Citizens United decision struck down campaign finance limits on political expression by individuals working through corporations and unions as a violation of the First Amendment's guarantee of freedom of speech. A cry ensued among liberal Democrats predicting doom if they and their special interest allies were required to follow the Constitution. Big Labor's bosses promised to spend millions to protect the Democratic majority if it would speedily pass legislation to circumvent the decision (and thus the Constitution), but restore limits on their corporate foes. The resulting DISCLOSE Act, according to its backers, will ensure transparency...