I'll admit it. I underestimated Tom Tancredo. I underestimated the impact he could make as a presidential candidate, particularly as a candidate who was polling, as many of us had predicted, around 2 percent. And yet, I had no idea he could take one issue and, with it, help make the Republican presidential race - and the country itself - an uglier, nastier and more mean-spirited place to be. He didn't do it by himself, of course. He wasn't even the lead player. You have to give that role to Lou Dobbs and the huge audience on his team. Still,...