The gridlock in Washington, we are told, is a casualty of both political parties veering to the extremes. To get things done, we need sensible moderates on both sides to make compromises.

But what if that’s wrong? What if the blame lies mostly with one side or the other?

You can say that on talk radio and cable TV. But most people dismiss Rush Limbaugh and Keith Olbermann as partisan cheerleaders trying to boost their ratings, not to find the truth.

Now, two respected centrist scholars, Norman Ornstein and Thomas Mann, have written a book that moves past the bland and lazy conventional wisdom. They argue, with a truckload of evidence, that the blame in Washington lies overwhelmingly with Republicans.

"I’m a raging moderate, and I’ve got very close friends on both sides of the aisle," says Ornstein. "So this was not an easy thing to do."

What’s the evidence? Consider that Ronald Reagan could not win a Republican primary today. He signed 11 tax hikes. And he granted amnesty to millions of illegal immigrants.

"Maybe the name Ronald Reagan would do it," says Ornstein. "But if you changed the name and had him run today on his record as president, he would be run out of town on a rail."

The Republican Party’s shift rightward is at the core of the standoff on the debt. Every bipartisan group, including two commissions and the Gang of Six in the Senate, has concluded that the solution must include tax increases.

But House Speaker John Boehner (R-Ohio) cannot sell that to his caucus. Of his 242 members, 238 of them have signed Grover Norquist’s pledge to oppose any tax increase. House Budget Chairman Paul Ryan (R-Wis.) would cut taxes even more, as would Mitt Romney.

"How are you going to solve the debt problem when you have even more tax cuts?" Ornstein asks.

On climate change, the party has simply lost touch with reality. Even sensible people such as New Jersey’s Rep. Leonard Lance (R-7th) have abandoned his support for comprehensive climate legislation.

The ability of this crowd to ignore facts is only the start of it. They also don’t play well with others, and see compromise as a sin.

Again, go to the evidence. Since President Obama took office, Republicans have voted in a bloc to oppose every major move he’s made, with the exception of a few trade treaties.

Excerpts from "It's Even Worse Than It Looks"

“We have been studying Washington politics and Congress for more than 40 years, and never have we seen them this dysfunctional. In our past writings, we have criticized both parties when we believed it was warranted. Today, however, we have no choice but to acknowledge that the core of the problem lies with the Republican Party.

The GOP has become an insurgent outlier in American politics. It is ideologically extreme; scornful of compromise; unmoved by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition.”

“‘Both sides do it’ or ‘There is plenty of blame to go around’ are the traditional refuges for an American news media intent on proving its lack of bias, while political scientists prefer generality and neutrality when discussing partisan polarization. Many self-styled bipartisan groups, in their search for common ground, propose solutions that move both sides to the center, a strategy that is simply untenable when one side is so far out of reach.”

“We understand the values of mainstream journalists, including the effort to report both sides of a story. But a balanced treatment of an unbalanced phenomenon distorts reality. If the political dynamics of Washington are unlikely to change anytime soon, at least we should change the way that reality is portrayed to the public.

Don’t seek professional safety through the even-handed, unfiltered presentation of opposing views. Which politician is telling the truth? Who is taking hostages, at what risks and to what ends?”

“If our democracy is to regain its health and vitality, the culture and ideological center of the Republican Party must change. In the short run, without a massive (and unlikely) across-the-board rejection of the GOP at the polls, that will not happen. ... It is up to voters to decide. If they can punish ideological extremism at the polls and look skeptically upon candidates who profess to reject all dialogue and bargaining with opponents, then an insurgent outlier party will have some impetus to return to the center. Otherwise, our politics will get worse before it gets better.”

Sen. Mitch McConnell of Kentucky, the GOP leader in the Senate, made it explicit early on: The goal is to undermine Obama, so he should be denied any wins that could sustain him.

"That’s different," Ornstein says. "George Bush came into office in one of the most contested elections in 100 years and Democrats didn’t start by saying ‘Let’s stomp his head.’ The first thing that happened is Ted Kennedy worked with him to get No Child Left Behind passed, and that was a huge political victory for Bush. He also wouldn’t have gotten tax cuts passed if not for Democratic support in the Senate."

DISEASE OF EXTREMISM

You can make credible arguments against the book. This is politics, not science.

Government spending is rising sharply, thanks mostly to the recession. The health care reform extends Washington's reach, and some consider that a sin even in the face of 50 million uninsured Americans.

And the disease of extremism is at its worst in Washington. Gov. Chris Christie is a pragmatist who does not remotely resemble the profile that Mann and Ornstein draw. He compromised to get health and pension reform for public workers, and is prepared to do the same on education reform. He says the scientists are right about climate change. And when he appointed the state’s first Muslim judge, he called the right-wing critics "crazies."

But you don’t hear that push-back in Washington. When a GOP congressman recently claimed that "78 to 81" Democrats were communists, none of the leadership made a peep.

Our national politics has turned a strange corner. And it is a cop-out to say that both parties are equally to blame. Strained attempts to be even-handed distort the reality we face.

MIGHT GET WORSE

Ornstein and Mann wrote a book on Congress six years ago and got an enthusiastic endorsement on the jacket from Newt Gingrich. But the Grand Old Party has changed since then.

"It’s ideologically extreme; scornful of compromise; unmoved by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition," they write.

The worst of this is still to come, because the standoff on the debt last summer was not resolved; it was postponed until after the election. Without an agreement, the Bush tax cuts will expire, driving up rates on everyone. The economy will get a second kick in the groin when deep spending cuts agreed to last summer kick in automatically in the absence of a new agreement.

"It’ll be like the ‘War of the Roses,’ " Ornstein says.

The book is titled "It's Even Worse Than It Looks" and it is both fascinating and alarming.

Yes, America has overcome even deeper divisions in the past. Five years before the Civil War, a Southern congressman used a cane to beat a northern senator, nearly killing him.

But how reassuring is that when we know how the story ended?