He didn’t announce anyone as his running mate, but GOP presidential front runner Mitt Romney spoke volumes with his one-word answers after getting grilled by Jay Leno about Obamacare and his impressions of Rick Santorum Tuesday night. When asked to give a one-word description of his Republican colleagues, he answered “Chris Christie” with “indomitable”; he answered “Marco Rubio” with “American Dream”; and he called Rep. Paul Ryan “creative.” And when asked about rival Rick Santorum — who this week called Romney “the worst Republican in the country to put up against Barack Obama” before also saying he’d consider being Romney’s running mate – Romney coolly quipped, “Press Secretary.”