By Paul Krugman — New York Times.

We’ve always known that America’s reign as the world’s greatest nation would eventually end. But most of us imagined that our downfall, when it came, would be something grand and tragic.

What we’re getting instead is less a tragedy than a deadly farce. Instead of fraying under the strain of imperial overstretch, we’re paralyzed by procedure. Instead of re-enacting the decline and fall of Rome, we’re re-enacting the dissolution of 18th-century Poland.

A brief history lesson: In the 17th and 18th centuries, the Polish legislature, the Sejm, operated on the unanimity principle: any member could nullify legislation by shouting “I do not allow!” This made the nation largely ungovernable, and neighboring regimes began hacking off pieces of its territory. By 1795 Poland had disappeared, not to re-emerge for more than a century.

Today, the U.S. Senate seems determined to make the Sejm look good by comparison.

Last week, after nine months, the Senate finally approved Martha Johnson to head the General Services Administration, which runs government buildings and purchases supplies. It’s an essentially nonpolitical position, and nobody questioned Ms. Johnson’s qualifications: she was approved by a vote of 94 to 2. But Senator Christopher Bond, Republican of Missouri, had put a “hold” on her appointment to pressure the government into approving a building project in Kansas City.

This dubious achievement may have inspired Senator Richard Shelby, Republican of Alabama. In any case, Mr. Shelby has now placed a hold on all outstanding Obama administration nominations — about 70 high-level government positions — until his state gets a tanker contract and a counterterrorism center.

What gives individual senators this kind of power? Much of the Senate’s business relies on unanimous consent: it’s difficult to get anything done unless everyone agrees on procedure. And a tradition has grown up under which senators, in return for not gumming up everything, get the right to block nominees they don’t like.

In the past, holds were used sparingly. That’s because, as a Congressional Research Service report on the practice says, the Senate used to be ruled by “traditions of comity, courtesy, reciprocity, and accommodation.” But that was then. Rules that used to be workable have become crippling now that one of the nation’s major political parties has descended into nihilism, seeing no harm — in fact, political dividends — in making the nation ungovernable.

How bad is it? It’s so bad that I miss Newt Gingrich.

Readers may recall that in 1995 Mr. Gingrich, then speaker of the House, cut off the federal government’s funding and forced a temporary government shutdown. It was ugly and extreme, but at least Mr. Gingrich had specific demands: he wanted Bill Clinton to agree to sharp cuts in Medicare.

Today, by contrast, the Republican leaders refuse to offer any specific proposals. They inveigh against the deficit — and last month their senators voted in lockstep against any increase in the federal debt limit, a move that would have precipitated another government shutdown if Democrats hadn’t had 60 votes. But they also denounce anything that might actually reduce the deficit, including, ironically, any effort to spend Medicare funds more wisely.

And with the national G.O.P. having abdicated any responsibility for making things work, it’s only natural that individual senators should feel free to take the nation hostage until they get their pet projects funded.

The truth is that given the state of American politics, the way the Senate works is no longer consistent with a functioning government. Senators themselves should recognize this fact and push through changes in those rules, including eliminating or at least limiting the filibuster. This is something they could and should do, by majority vote, on the first day of the next Senate session.

Don’t hold your breath. As it is, Democrats don’t even seem able to score political points by highlighting their opponents’ obstructionism.

It should be a simple message (and it should have been the central message in Massachusetts): a vote for a Republican, no matter what you think of him as a person, is a vote for paralysis. But by now, we know how the Obama administration deals with those who would destroy it: it goes straight for the capillaries. Sure enough, Robert Gibbs, the White House press secretary, accused Mr. Shelby of “silliness.” Yep, that will really resonate with voters.

After the dissolution of Poland, a Polish officer serving under Napoleon penned a song that eventually — after the country’s post-World War I resurrection — became the country’s national anthem. It begins, “Poland is not yet lost.”

Well, America is not yet lost. But the Senate is working on it.