WASHINGTON -- Congressman Collin Peterson was on a flight back to Washington this summer with U.S. Sen. Chuck Grassley, a key Republican negotiator on President Obama's health care overhaul.

The long plane ride from Minneapolis gave the Minnesota Democrat and the Iowa Republican, both relishing their roles as party spoilers, a chance to compare notes on the tempestuous partisan debate swirling around them.

"He's under a lot of pressure from GOP leadership," Peterson said.

Peterson, a guitar-slinging, gun-toting maverick who often goes his own way, could easily have been talking about himself. As a founder of the fiscally conservative "Blue Dog" coalition, Peterson is part of a group of 52 mainly rural Democrats who have bedeviled the White House by blocking a proposed government-run insurance program known as the "public option."

"I go against my party sometimes, and it's not easy," Peterson said. "You come under a lot of pressure. Peer pressure and leadership pressure. But in the end, cooler heads will prevail."

For now, that day of cooler heads seems a long way off.

Instead, Peterson finds himself on the receiving end of liberal attacks calling the Blue Dogs "brain dead," and GOP attack ads in his northwestern Minnesota district likening the Democrats' health care plans to the fictional wonder drug "Reforma" ("recommended by more lobbyists than any other health reform").

He's also taken flak for saying "I don't do town meetings," equating extremists who sometimes take over public gatherings with 9/11 conspiracy theorists.

In the end, though, Peterson attended several town hall meetings, buzzing around the state, as usual, in the single-engine, v-tail Beechcraft Bonanza he pilots. The overflow crowds were mostly Minnesota Nice, even if he did receive a smattering of boos in Bemidji -- a rarity for a 10-term congressman who won his last election with more than 72 percent of the vote.

Good votes, bad votes

"Collin has had some good votes, and he's had some bad votes," said Beltrami County GOP Chairman Ken Cobb, who was at the town hall meeting in Bemidji. To Cobb, one of the bad ones was Peterson's vote in favor of cap-and-trade legislation to limit greenhouse gases, which conservatives see as an unwarranted energy tax.

Even worse, conservatives say, would be if Peterson were to line up behind his party leaders on a government-run health plan, something Peterson says he won't do.

"People are watching health care very closely," said Scott Hennen, a conservative radio host who moderated a recent town hall meeting with Peterson in Moorhead. "He's saying the right things right now. But it will be a trust-but-verify type deal."

Fully aware that Minnesota's Seventh Congressional District would likely fall into Republican hands without a strong Democrat who opposes abortion such as Peterson, Democratic leaders tend to give the Detroit Lakes native all the leeway he wants.

Minnesota DFL Party Chairman Brian Melendez, defending Peterson against recent GOP attacks, called him "a fearless and independent voice for greater Minnesota."

Peterson, 65, boasts of his votes against the Wall Street bailout, "cash-for-clunkers" and the stimulus bill - which all passed with large Democratic majorities. Even his vote for cap-and-trade came only after a hard-fought battle against the White House to protect farmers. For Peterson, whose dad still owns and rents out the family farm, this is a critical constituency.

A Democratic firewall

Now Peterson and his fellow Blue Dogs are serving as a Democratic firewall against a public option. Obama, caught in the middle, has been forced to retreat, telling a joint session of Congress this week that while he favors a public option, Democrats need to be "open to other ideas."

With his trademark cowboy boots planted firmly on the middle ground, Peterson urges the partisans on both sides to "get off their high horses" and compromise. His bottom-line issue: fixing regional Medicare disparities that penalize low-cost, high-efficiency health care providers in Minnesota.

"If the Medicare disparities aren't fixed," he said, "I'm not voting for this bill. I don't give a damn what's in it."

In the battle over a public option, the Blue Dogs seem to hold the best cards. It is they -- not their liberal counterparts in the cities -- who face the toughest fights in next year's midterm elections.

"Blue Dogs like Peterson are much more likely to stay unified," said Kay Wolsborn, a political science professor at the College of St. Benedict and St. John's University in Collegeville, Minn.

Republicans plan to leverage populist discontent with Obama's health care plan to win conservative districts such as Peterson's. "He's a Democrat in a Republican district," said Tony Sutton, chairman of the Minnesota GOP. "We're not going to let him off the hook."

But the extra attention hasn't been all bad. The American Future Fund, a conservative group, has just announced a national television campaign defending the Blue Dogs, including Peterson. The Minnesota script, which starts, "Is our congressman, Collin Peterson, brain dead?" refers to Rep. Pete Stark, D-Calif., who recently called the Blue Dogs "brain dead" and beholden to insurance companies.

In fact, the Blue Dog Political Action Committee has raked in more than $1.1 million for the 2010 election cycle, the most of any other leadership PAC on Capitol Hill, according to CQ MoneyLine. About $300,000 of that came from health care interests.

Still, while the pressure from lobbyists and party leaders promises to intensify as the end-game of the health reform debate approaches, Peterson says he's not feeling the heat.

"They know better than to pressure me on this," he said.

Kevin Diaz • 202-408-2753