Barack Obama and Mitt Romney Start Squaring Off

After yesterday's wins in Wisconsin, Maryland, and the District of Columbia, Mitt Romney is acting like he's the Republican nominee to challenge President Obama.  Today, as the President did yesterday, Romney addressed the convention of news executives, and accused Obama of running a "hide and seek" campaign. He referred to the President's accidentally recorded comment to Russian President Dimitri Medvedev—that he'd have more "flexibility" after his re-election. Romney called that a "defining event." But Rick Santorum is not conceding the GOP nomination yet.