BOSTON — The Republican Party was the model of unity leaving its national convention barely two months ago. But no more. Displaying a fracture that stands to become a clean break if John McCain loses the election next week, Republicans of all stripes and stature have broken with their party's nominee and are not only supporting Democrat Barack Obama, but trashing the GOP in the process. Former Sen. Charles Mathias of Maryland wrote Tuesday in The Washington Post: "For me, the decision is based on the long-range needs of our country and which of these two candidates I feel is...