WASHINGTON — Republicans have seen, in rather high-profile fashion, the thinning of the ranks of their party’s moderates (think of U.S. Sen. Dick Lugar’s defeat in last week’s Indiana primary), but they’re not the only ones.

The Blue Dog Coalition of fiscally conservative Democrats is half the size it was in 2010, thanks in large part to the retirement of its members, the general election defeat of many others, and, in more recent cases, challenges from a more liberal ilk of Democrat.

Minnesota U.S. Rep. Collin Peterson was the seventh House Democrat to join the group when it formed in 1994. He said there is still room in Congress for a centrist coalition like the Blue Dogs, but said that the leftward swing of newly elected Democrats is partially to blame for both the group’s shrinking numbers and the partisanship crippling Washington.

For the coalition to thrive again, as Peterson says it can, it’ll have to weather a left-ward turn by new Democratic House candidates and the ever-present threat from Republicans, whose target is always trained on Blue Dogs come election year.

'We were invited into the room'

The Blue Dog Coalition formed on eve of the 1994 election that swept Republicans into the majority in the U.S. House, its name derived from an old saying that Southerners would vote for a yellow dog if it was running as a Democrat. The Blue Dogs were yellow dogs "choked blue" by their more liberal colleagues.

Peterson was the seventh member of what, at the time, was an exclusive group of lawmakers whose preferred ideology was one of fiscal conservatism with a healthy desire to work with both mainstream Democrats and Republicans alike.

And for a while, that’s how it worked. Both parties looked to compromise with the centrist Blue Dogs, especially when the margin between the majority and minority parties was especially small and the centrist vote was, by extension, especially important.

“We were invited into the room,” Peterson said.

At the time, the Blue Dogs were so exclusive that a single dissenting member could keep a lawmaker from joining their ranks. (The goal was “try to find people that are ideologically compatible,” Peterson said.) The meetings were conducted by members only — unlike other caucuses on Capitol Hill, staffers were not allowed to sit in for lawmakers — and those who didn’t show up were dismissed from the group.

Those rules grew more lax around the late 1990s, and the group’s influence waned as the size of the majorities grew larger. In 2006, when Democrats took back control of the House, Peterson said Democratic leadership wasn’t interested in Blue Dog appeals that the party move slowly and not pursue costly big-government bills. But that’s just what they did, especially after President Obama took office, when the House passed the stimulus bill, cap and trade legislation, and health care reform, all of which Peterson and other Blue Dogs opposed.

Electoral problems

The Blue Dog Coalition had 54 members on November 2, 2010, when voters swept Democrats out of power in the House. Between retirements, resignations and general election losses (many Blue Dogs represent moderate districts or even those that skew a bit to the right, thus making them top targets for Republicans) they have only 25 members today.

 And things are going to get worse for the moderates before they get better, said Norm Ornstein, a congressional scholar at the American Enterprise Institute think tank.

“Over a long period of time Democrats have become far more homogenous and moved left,” he said.

Ornstein is out with a new book, called “It’s Even Worse Than It Looks,” detailing the increased polarization of the two parties, and though the book places most of the blame on Republicans (which is a different story entirely), he said Democratic moderates face their challenges as well.

First, redistricting was unkind to them, especially in states where Republicans controlled the Legislature. Increased outside spending on critical races in tight districts will also hurt them, as will the threat of primary challenges from the left.

Two Blue Dogs witnessed that first hand in April, when Pennsylvania Reps. Jason Altmire and Tim Holden lost primaries against more liberal Democrats. Through redistricting, Altmire was paired with his colleague, U.S. Rep. Mark Critz, who, while not a diehard liberal himself, used Altmire’s vote against Obama’s health-care package to snag the endorsement of labor unions and former President Bill Clinton. Holden’s opponent, an attorney named Matt Cartwright, was aided by an anti-incumbent super PAC that targeted Holden.

NRCC targets

Between those two losses and the retirements of others, the Blue Dogs are going to be at least seven members down by next session — and that’s if all the rest survive the general election.

The National Republican Congressional Committee is taking aim at the remaining Blue Dogs this fall. Of the 18 Blue Dog re-election campaigns, six have Republican challengers on the NRCC’s list of potential "Young Gun" candidates, up-and-coming Republicans in winnable races (Peterson’s opponent, Lee Byberg, is not on the list).

The NRCC is “aggressively targeting these so-called moderate Blue Dog members who say one thing in their home districts and vote another way in Washington,” spokeswoman Andrea Bozek said.

But if the Blue Dogs survive, and if, as Peterson predicts, whichever party holds the majority does so by only a few votes, Peterson said he could see the coalition controlling valuable real estate as the centrist votes both parties need to enact legislation.

As for the decline of the political middle in general, Peterson said that’s in the voters’ hands.

“If you want to vote Republican or Democratic, I don’t care how you vote, but don’t vote for anybody in any party that is going to vote party line.”

Devin Henry can be reached at dhenry@minnpost.com. Follow him on Twitter: @dhenry