Free Trade and the Presidential Campaign

Democrats in Pennsylvania, Indiana and North Carolina will be voting next week. Obama and Clinton have been exchanging barbs about "bitter" voters, religion and guns. In tomorrow's final debate, one issue that might come up is free trade, including the deal with Colombia. Would it be good or bad for American workers? Why are Democratic leaders opposing what they've supported before? Also, deadly bombings destroy weeks of calm in Iraq, and income taxes are due at midnight. What about next year? We hear what the presidential candidates are proposing.