After four straight daily surveys that showed Barack Obama and Hillary Clinton essentially even in its daily tracking polls, today’s Gallup offering has Obama ahead 48 percent to 43 percent for the second straight day. The margin of error is 3 percent and the poll was conducted Feb. 25-27. . John McCain leads Mike Huckabee 61 percent to 24 percent. The daily tracking poll has been showing more modest national leads for Obama than several other major polls, including the one that Gallup does for USA Today.