An early look at potential 2012 match-ups indicates that the election is likely shaping up as a referendum on President Obama. That’s typical when an incumbent runs for reelection. The numbers show that Mitt Romney and Mike Huckabee essentially run even with Obama at this point. Romney is nominally up two points, 44% to 42%, while Huckabee is tied with the president at 43% apiece. Three other well-known potential candidates, Sarah Palin, Newt Gingrich and Ron Paul trail the president. Palin is down by 11 points, 49% to 38%, Gingrich by eight, 47% to 39%, and Paul by nine, 44%...