“This is just one of those days when you want to throw up your hands and say, ‘What in the world are we doing?’ ” Senator Claire McCaskill, the Missouri Democrat, said.

“It’s unconscionable,” Carl Levin, the senior Democratic senator from Michigan, said. “The obstructionism has become mindless.”

The Senators were in the Capitol, sunk into armchairs before the marble fireplace in the press lounge, which is directly behind the Senate chamber. It was four-thirty on a Wednesday afternoon. McCaskill, in a matching maroon jacket and top, looked exasperated; Levin glowered over his spectacles.

“Also, it’s a dumb rule in itself,” McCaskill said. “It’s time we started looking at some of these rules.”

She was referring to Senate Rule XXVI, Paragraph 5, which requires unanimous consent for committees and subcommittees to hold hearings after two in the afternoon while the Senate is in session. Both Levin and McCaskill had scheduled hearings that day for two-thirty. Typically, it wouldn’t be difficult to get colleagues to waive the rule; a general and an admiral had flown halfway around the world to appear before Levin’s Armed Services Committee, and McCaskill’s Subcommittee on Contracting Oversight of the Homeland Security Committee was investigating the training of Afghan police. But this was March 24th, the day after President Barack Obama signed the health-care-reform bill, in a victory ceremony at the White House; it was also the day that the Senate was to vote on a reconciliation bill for health-care reform, approved by the House three nights earlier, which would retroactively remove the new law’s most embarrassing sweetheart deals and complete the yearlong process of passing universal health care. Republicans, who had fought the bill as a bloc, were in no mood to make things easy.

So, four hours earlier, when Levin went to the Senate floor and asked for consent to hold his hearing, Senator Richard Burr, Republican of North Carolina, and a member of Levin’s committee, had refused. “I have no personal objection to continuing,” Burr said. But, he added, “there is objection on our side of the aisle. Therefore, I would have to object.”

Burr had to object on behalf of his party because he was the only Republican in the chamber when Levin spoke. In general, when senators give speeches on the floor, their colleagues aren’t around, and the two or three who might be present aren’t listening. They’re joking with aides, or e-mailing Twitter ideas to their press secretaries, or getting their first look at a speech they’re about to give before the eight unmanned cameras that provide a live feed to C-SPAN2. The presiding officer of the Senate—freshmen of the majority party take rotating, hour-long shifts intended to introduce them to the ways of the institution—sits in his chair on the dais, scanning his BlackBerry or reading a Times article about the Senate. Michael Bennet, a freshman Democrat from Colorado, said, “Sit and watch us for seven days—just watch the floor. You know what you’ll see happening? Nothing. When I’m in the chair, I sit there thinking, I wonder what they’re doing in China right now?”

Between speeches, there are quorum calls, time killers in which a Senate clerk calls the roll at the rate of one name every few minutes. The press gallery, above the dais, is typically deserted, as journalists prefer to hunker down in the press lounge, surfing the Web for analysis of current Senate negotiations; television screens alert them if something of interest actually happens in the chamber. The only people who pay attention to a speech are the Senate stenographers. On this afternoon, two portly bald men in suits stood facing the speaker from a few feet away, tapping at the transcription machines, which resembled nineteenth-century cash registers, slung around their necks. The Senate chamber is an intimate room where men and women go to talk to themselves for the record.

Like many other aspects of senatorial procedure, Rule XXVI, Paragraph 5 is a relic from the days when senators had to hover around their desks to know what was happening on the floor during the main afternoon debate. (The desks, some built as long ago as 1819, are mahogany, and their lids lift up, like those in an old schoolhouse; the desks of the Majority and Minority Leader are still equipped with brass spittoons.) In the press lounge, McCaskill said, with light sarcasm, “Somebody told me the rule is to make sure people pay attention to what’s happening on the floor during debate and not be distracted by committee work. Clearly, it’s an old rule.”

The Republicans had turned this old rule into a new means of obstruction. There would be no hearings that afternoon; the general and the admiral would have to come back another day. Like investment bankers on Wall Street, senators these days direct much of their creative energy toward the manipulation of arcane rules and loopholes, scoring short-term successes while magnifying their institution’s broader dysfunction.

Around five o’clock, the chamber began to fill, as the reconciliation bill came up for a vote; there were twenty-three amendments pending, all from Republicans, and perhaps many more to come. Ordinarily, debate and voting on an amendment might take two legislative days, but under the rules of the reconciliation bill the senators were to dispatch the amendments one after another, as in a hot-dog-eating contest, with a minute of debate for each side. The goal was to finish the bill by the end of the evening, so that senators wouldn’t miss a day of their spring recess—apparently, the only thing worse than a government takeover of the health-care system. The usual longueurs of the Senate, where forty minutes can tick away on the antique clock above the rear double doors without a word’s being spoken, were about to yield to a frenzy. Harry Reid, the Majority Leader, from Nevada, had predicted that the process, known as Vote-O-Rama, would go past two in the morning, and had warned senators to stay close to the chamber.

Max Baucus, of Montana, the manager of the bill for the Democrats, rose and said, “This is the first time in recent memory that a reconciliation bill has all the amendments on one side only. These are clearly amendments designed to kill the reconciliation and, therefore, kill health-care reform. So I very much hope that all of these amendments are defeated.”

Tall, gaunt Judd Gregg, of New Hampshire, the bill’s Republican manager, took the floor. “The position on the other side of the aisle is: no amendments allowed, even if they are good,” he said. Indignation rouged his cheeks, and his voice rose half an octave. “Obviously, they presume the Republican Party is an inconvenience. The democratic process is an inconvenience. It also appears, considering the opposition to this out in America, that the American people are an inconvenience.”

The Senate chamber is laid out in four concentric semicircles, with adjacent desks almost touching on the crowded Democratic side, and the desks of the much smaller Republican minority spaced loosely apart. The design is meant to emphasize the senators’ unity. But Baucus and Gregg avoided eye contact across the six feet of aisle that now divides the chamber into two constantly warring factions. Senators are required, by custom, to speak of one another in the third person, directing their anger and sarcasm through whichever poor freshman happens to be the presiding officer at the moment. Rule XIX, Paragraphs 2 and 3—one of the original rules drawn from Thomas Jefferson’s “Manual of Parliamentary Practice”—bars senators from imputing unworthy conduct or motives to another senator, and from insulting any senator’s state. But there is no rule against finger-wagging, and Baucus wagged his at Gregg while shouting at Al Franken, of Minnesota, who had started a shift in the presiding officer’s chair: “Mr. President, make no mistake, the intent of every single one of the amendments offered on the other side of the aisle is to kill health-care reform. . . . A senator on the other side of the aisle stood up and said that this is hopefully the President’s Waterloo. They want to kill health-care reform!”