President Obama did something extraordinary, perhaps unprecedented, in his news conference immediately after the midterm elections: He claimed a mandate on behalf of voters who didn't vote."To everyone who voted, I want you to know that I hear you," the president said. "To the two-thirds of voters who chose not to participate in the process yesterday, I hear you, too."What did that mean? What did those non-voters say?The president explained that many more voters turned out when he was elected, and then re-elected, than in the midterms that left Republicans firmly in control of the House and Senate.