WASHINGTON - It's a tough time to be a moderate in Congress.
Just two years removed from being one of Capitol Hill's most powerful voting blocs, centrist Democrats like U.S. Rep. Collin Peterson are now something of an afterthought.
In the early years of President Obama's administration, members of the Blue Dog Coalition, a conservative Democratic caucus, were among the most influential in the House. Leaders from both parties coveted their swing votes on legislation ranging from federal health care to budget bills.
Now the Blue Dogs' bark has become more of a whimper. Political forces have decimated their ranks and influence, leaving just 15 members of a pack that once stood more than 50 strong.
"No one is asking us anything," Peterson said. "We've been marginalized."
Peterson cruised to re-election last month with more than 60 percent of the vote in a conservative-leaning district, but many of his Blue Dog compatriots were less fortunate. Once-a-decade redistricting left some vulnerable to partisan challengers. Several veteran members lost primaries to more-liberal Democrats. Others opted to retire rather than face uphill re-election battles.
As Peterson begins his 12th term in Congress next year, experts say he and his ilk face a fight for relevance in what could be the most polarized Congress in recent memory.
"I don't think there is a rebound for them," said Calvin Jillson, a political science professor at Southern Methodist University in Dallas.
The lack of moderates has political implications beyond the Blue Dogs' shrinking circle. The lack of centrists could make it even harder to piece together coalitions to pass bills next year, said University of Georgia political scientist Keith Poole.
That's a bold prediction considering the low-water mark of the current Congress. Its members have passed fewer than 200 bills. That's a lower number than any session since 1947.
When Congress reconvenes in January, doctrinaire Republicans will dominate the House, making compromise with Democrats even less likely. With so few centrists left, there aren't enough House members in the political center to incite cooperation, said Isabel Sawhill, a senior fellow at the Brookings Institution in Washington.
As the lead Democrat on the House Agriculture Committee, Peterson has seen firsthand evidence of that. Paralyzed by gridlock, the House has yet to approve the farm bill -- a critical piece of legislation for residents in Peterson's mostly rural district.
In many ways, the House tug-of-war over the farm bill mirrors the ongoing "fiscal cliff" budget negotiations. Because of changes that stretch back a decade, the farm bill is now composed mostly of spending on the U.S. food stamp program -- about 80 percent. Republicans oppose that level of spending and many Democrats are resisting cuts that would affect food-stamp recipients.
"I'm frustrated and so are the American people," Peterson said.
After more than two decades in Congress, Peterson is the senior member of the Minnesota delegation and its honorary dean. But his politics provide little opportunity to serve as any kind of senior spokesman -- even among Democrats -- in part because Minnesota's delegation so perfectly embodies the deep partisan divide in Congress.
On one end is U.S. Rep. Keith Ellison, co-chairman of the Progressive Caucus and one of the most liberal Democrats in the House. On the other stands Michele Bachmann, the most visible member of the conservative Republican Tea Party caucus. Peterson operates in the political center as a centrist who is reluctant to follow his party's line.
Of Minnesota's 10-member House and Senate delegation, nine vote with their party roughly 90 percent of the time. Peterson is the lone exception: He votes with Democrats just 57 percent of the time.
"He always caught a little bit of flak from both sides," said Steve Veverka, a Minnesota public affairs consultant and former Peterson campaign manager. "But he's been around long enough that people shouldn't be surprised at how he votes."
Peterson has opposed two of the president's major initiatives -- the federal stimulus package and the Affordable Care Act that is reshaping U.S. health care.
Earlier this year, Peterson lost the endorsement of Minnesota Citizens Concerned for Life, a group that lobbies against legalized abortion, after he said that the health care legislation, often referred to as Obamacare, is "not all bad."
Acquaintances and colleagues say that comment is a sign of the strong independent streak that has marked Peterson's congressional career.
"There are some DFLers who vehemently disagree with his stances on the issues," said state DFL Party Chairman Ken Martin. "But he's earned their trust over the years."
Peterson also has earned the respect of Republicans in Washington. The National Republican Congressional Committee, which works to elect candidates to the House, has not backed a Peterson opponent in at least a decade.
Peterson, 68, is one of just 10 Minnesotans who have served 20 years in Congress. With no immediate plans to retire, he intends to press on, even though the Blue Dogs have become an increasingly rare breed.
"Collin's a survivor," Veverka said. "He'll do fine."
Corey Mitchell is a correspondent in the Star Tribune Washington Bureau. Twitter: @CMitchellStrib