Pelosi is a fighter...she's done a great job holding the Dem Reps in line and has brought back an edge of "consequences" to be paid for those who choose to cast their lot with the GOP. Here's an example from the Medicare debacle last year (source - WP):
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Soon after Rep. Steve Israel (N.Y.) joined eight other House Democrats in voting for a Republican version of a major Medicare bill last summer, Minority Leader Nancy Pelosi (D-Calif.) summoned him to her office.
"She was very clear and very firm in making sure I understood the caucus position on the bill and that unity was very important," Israel recalled. "It was not the happiest conversation I've had in politics."
In the end, however, he did not resent the dressing down. "I didn't leave the room with any questions about where she stood," he said. "It's an extremely refreshing sign of leadership. There's no guesswork."
<snip>
http://www.washingtonpost.com/ac2/wp-dyn/A21912-2003Nov29?language=printer