In the newest installment of a continuing attack on Mitt Romney’s record as governor of Massachusetts, an ad from the Obama campaign takes aim at the Bay State’s debt load. The ad, released June 12, 2012, has the ironic title "Number One," claiming that "when Mitt Romney was governor, Massachusetts ... (had) more debt per person than any other state in the country." First, here's a primer on state debt and how it differs from the national debt. Because the United States is a sovereign nation that can print its own money, it is able ...