The best line of the debate came from Fred Thompson after Mitt Romney unleashed a canned joke about how the presidential campaign is a little like Law and Order: "This is a lot like 'Law & Order,' Senator. It has a huge cast, the series seems to go on forever, and Fred Thompson shows up at the end." I thought I was going to be the best actor up here, Thompson said (I'm paraphrasing), referring to Romney. It's a measure of Thompson's political skills that his (probably also canned) line came across much smoother, and funnier, than Romney's. In fact, Thompson had a string of good lines at the end. Chris Matthews tried to get Thompson to flub the name of the Canadian prime minister, but Thompson knew who Stephen Harper is. Then, when asked his relationship with Harper, Thompson said: We get along fine - We've never met. The audience laughed, and Thompson grinned widely. Never underestimate the power of political humor. One good debate doesn't make a campaign, but one bad debate can ruin a campaign. In my view, none of the top four candidates had a bad debate, though Romney came close when he said he would more or less cede command authority to his lawyers during a crisis involving the use of force. So: The race remains unchanged.