The U.S. Supreme Court's decision today in Citizens United v. FEC, which reversed two previous decisions and invalidated part of the McCain-Feingold Campaign Finance Deform act, was especially pleasing to me. I was in Washington when the original campaign finance restrictions were passed post-Watergate, and I thought and wrote at the time that the real purpose -- and certainly the effect -- of limits on donations and campaign spending was incumbent protection. If you "level" the playing field, the tilt goes to the incumbent, who has incumbency, name recognition, the ability to dispense favors (or seem to; agencies let Congresscritters announce new federal projects in the district first even if they had nothing to do with getting them), and a taxpayer-paid staff devoted mostly to inflating the reputation of the Member and often (however technically illegal) working directly on reelection campaigns.
In addition, of course, rules like the McCain-Feingold prohibition of anything that could be remotely be called electioneering by issue-oriented organizations within 30 or 60 days of an election is a limitation on free speech -- outright censorship, as Justice Kennedy recognized -- at precisely the time when freedom of speech should be most robust, as this Register editorial explains and argues.
Ilyas Shapiro (with whom I talked today) and John Samples of Cato make some similar points more elaborately in this op-ed.