In Yesterday’s Pennsylvania Democratic primary two incumbent members of the Blue Dog Coalition, Jason Altmire and Tim Holden, lost their re-election bids to more liberal opponents.

In the newly drawn 12th district Altmire was forced into a race against fellow Democratic congress member Mark Critz.  Altmire had an inherent advantage, because the new district contained more of his old district, but he was narrowly beaten by Critz. Critz had the backing of a large collection of labor unions and Bill Clinton. While Critz is not exactly a diehard liberal, he did depict himself as being more in line with the Democratic values than Altmire. Much of the campaign against Altmire was focused on his being too conservative and siding too often with Republicans.

In the new more Democrat-heavy 17th district Matt Cartwright easily beat long time incumbent Holden using a similar message. Cartwright framed himself as member of the “Democratic Wing of the Democratic Party” who thinks the Democrats have compromised too much with Republicans in Congress. Cartwright drew a sharp ideological contrast between himself and the much more conservative Holden, and it worked very well.

Between the big losses in the 2010 general election, retirements and these primaries the Blue Dog Coalition has seen its numbers radically reduced. Unless newly elected freshmen choose to join the coalition at this point, the coalition’s membership should be down to just 18 Representatives next year. By comparison in 2008 they had 54 members.

With these two victories showing that being a Blue Dog can be a serious liability in a primary, I suspect their efforts to recruit new members will become much more difficult.