Photograph of Barack Obama at a rally in Virginia Beach by Rick Bowmer/AP Barack Obama won yesterday's Maine caucus, with about 57-60% of the vote to Hillary Clinton's approximate 40-42%. This makes Obama's fourth win in a row, after sweeping the Democratic contests in Louisiana, Nebraska, and Washington yesterday. About 8 inches of snow fell in Maine, but voters were still lined up outside some doors. Politico's Ben Smith writes:Obama's victory comes despite being......