In fairness to the much-maligned GOP field, they face a formidable hurdle: how to credibly attack Obama when he has adopted so many of their party’s defining beliefs. Depicting the other party’s president as a radical menace is one of the chief requirements for a candidate seeking to convince his party to crown him as the chosen challenger. Because Obama has governed as a centrist Republican, these GOP candidates are able to attack him as a leftist radical only by moving so far to the right in their rhetoric and policy prescriptions that they fall over the cliff of mainstream acceptability, or even basic sanity.