Transition: Barack Obama campaigned on a promise to change the partisan tone in Washington. So why did he pick a take-no-prisoners partisan for his chief of staff?The high-level White House selection of fellow Chicagoan Rep. Rahm Emanuel, the sharp-elbowed, foul-mouthed head of the Democrat caucus, doesn't exactly augur well for the kind of noncynical air-freshening Obama voters had hoped for. After Emanuel helped the Democrats win Congress in 2006, he told a gathering of celebrating staffers and campaign workers that Republicans "can go f*** themselves," according to Chicago Tribune reporter Naftali Bendavid in her book, "The Thumpin': How Rahm Emanuel...