By Mark Willen, Senior Political Editor May 19, 2008 Mike Huckabee made it plain over the weekend that he'd love to be John McCain's running mate. He also made it plain that picking him would be the biggest mistake McCain could make. Huckabee has a lot of supporters and they're enthusiastic, devoted -- even rabid-sounding in some cases. But they tend to view the former Arkansas governor through rose colored glasses. Yes, he's charming and witty and very conservative on social issues. And he deserves credit for telling the truth (before taking it back) on immigration and the need to raise taxes in some circumstances (like when the government is broke). But his totally tasteless joke about aiming a gun at Barack Obama (before the NRA, no less) was disastrous. Take a look at the video and tell me a mere apology is enough to put it behind him. It's not. The remark shows callousness, carelessness and bad judgment. Add that to his lack of foreign policy experience. How can Republicans accuse Obama of being naive, inexperienced and lacking the necessary gravitas to be president, a charge McCain now makes almost every day, if Huckabee is on the GOP ticket? To be sure, Huckabee would bring some strengths -- he'd help mobilize evangelicals and conservatives, especially in the South. But he's unpredictable to say the least, and he's very much untested. Some of his campaign planks were unrealistic (making the U.S. energy independent in four years, for example.) For every conservative he'd excite, he'd turn off two independents, and McCain can't win without independents. Plus, you can't count a single electoral vote he'd add to what McCain already expects. If there was any doubt about Huckabee's fitness for the second spot on the ticket, the NRA joke eliminated it. The cardinal rule of vice presidential picks is to make sure it's someone who will do no harm. That can't be said of Huckabee. Better he get his own talk show.