If Mitt Romney's most pressing consideration in selecting a running mate is to find someone who can expand his appeal among independents or a critical demographic that remains up for grabs, several candidates would likely fit the bill better than Mike Huckabee. But if the former Massachusetts governor instead concludes that his right flank is not as secure as it needs to be, Huckabee may be among his best options. The winner of the 2008 Iowa caucuses remains one of the most popular and well-recognized conservatives nationwide, and his decision not to launch a second presidential run removed what might...