Washington (CNN) – His party got its clock cleaned in Tuesday's midterm elections, but according to a new national poll President Obama remains competitive in hypothetical 2012 presidential election matchups, especially against Sarah Palin. A CNN/Opinion Research Corp. survey released Thursday also indicates that at the unofficial start of the race for the Republican presidential nomination, the field of possible contenders appears wide open with no front-runner. According to the poll, 21 percent of Republicans say they would most likely support former Arkansas Gov. and 2008 GOP White House candidate Mike Huckabee for their party's 2012 presidential nomination, with 20...