The Republican Party is destroying America.

Harsh words, yes. But inescapably true. It’s a bit of a murder-suicide. House Republicans’ willingness to lay waste to the country to satisfy their fringiest faction will ultimately guarantee the GOP irrelevancy as a national party, unless they change their ways. In the meantime, they seem determined to take us all down with them.

There isn’t even a feint toward decency. In what has become a recurring nightmare, House Republicans are using budget negotiations to play chicken with the stability of the American economy. This time, they want President Obama to agree to defund his signature achievement, the Affordable Care Act. If he refuses to strangle his own baby in the crib, Republicans are happy to retaliate. They’ll shut down the government. These are not people with whom one can work.

Last year, Norm Ornstein of the American Enterprise Institute and Thomas Mann of Brookings wrote a book about this dysfunction known as the new Republican Party. It’s Even Worse Than It Looks: How the American Constitutional System Collided With the New Politics of Extremism makes a compelling case that the problems in Washington are not the result of “both sides”—the oft-preferred media frame—but of a GOP that has become all but unrecognizable to most Americans.

Ornstein and Mann, both widely respected as straight shooters, describe themselves as moderates and have had long careers working with both parties. In an interview this week, they expressed exasperation with the GOP’s behavior in the debt-limit and budget negotiations. Ornstein lamented that the title of the book today would be It’s Even Worse Than It Was.

Said Ornstein: “The bizarreness of this monomaniacal focus on Obamacare, given that it is fundamentally a Republican program from the 1990s mixed in with Romneycare,” says it all. “Obamacare relies on the private sector; there is no public option. That you are willing to bring the country to its knees to sabotage it … just shows this is a party that has gone off the rails.”

Just how damaging have the congressional Republicans been to the country? “If you look at what could have happened in a reasonable political system, with give and take … we would have been on a more robust path to growth,” said Ornstein. “We’ve gone from one credit agency downgrading us to a far greater likelihood that we will default. If sequester continues … it is a cancer eating away at national parks, food safety, basic research … it’s a terrible situation. No matter how much [Republicans] talk about how it was Obama’s idea … the whole idea was to create such awful consequences that no sane person would accept it. But these aren’t sane people.”

GOP stalwarts have framed criticisms of the party as attempts to make it more liberal. That is self-serving denial. The legitimate complaint about the new Republican Party, one you will hear frequently even from Republicans speaking privately, is that it is intransigent and beholden to its most radical elements. Having principles is fine. Imposing them on everyone else through destructive maneuvering that keeps the country constantly on edge is not.

“You have to accept the legitimacy of the other side,” said Mann. Today’s GOP, which exists to oppose all things Obama, does not.

“One of the things we don’t want to see is the demise of the Republican Party,” he said. “We aren’t looking for a GOP that becomes a center left or even a party that is right in the center. It’s always going to be a conservative party. We tried to make the point in the book that you can be very conservative in your policy views and want to solve problems. Or you can be revolutionary and want to get bloodshed.”

Ornstein said the two aren’t taking sides. “We want a Republican Party that returns to problem-solving mode,” he said. “We are suggesting that what works in American politics and our system is when parties focus on how you can solve the big problems and how you can have some give and take. There is one party that has lost its way and is being dominated by people who by historical standards are on the fringe.”

Both men agree that the GOP will likely get worse before it gets better. How is that possible, you ask? Looks like we are about to find out.