The Buckley rule By Charles Krauthammer Friday, September 17, 2010 Tuesday in Delaware was a bad day not only for Republicans but also for conservatives. Tea Partyer Christine O'Donnell scored a stunning victory over establishment Republican Mike Castle. Stunning but pyrrhic. The very people who have most alerted the country to the perils of President Obama's social democratic agenda may have just made it impossible for Republicans to retake the Senate and definitively stop that agenda Bill Buckley -- no Mike Castle he -- had a rule: Support the most conservative candidate who is electable. A timeless rule of sober...