An extraordinary political drama played out this past week in the U.S. House of Representatives as Democratic and Republican lawmakers feuded over a proposal aimed at watering down part of a key law passed after the September 11, 2001 terrorist attacks.

The spectacle, which provided a glimpse into the mechanics of politics on Capitol Hill, came as Congress works to complete unfinished business before a long summer recess.

Democrats shouted "shame, shame, shame" on the floor of the House, and arguments in the moments that followed represented the biggest display of partisan discord since a high-publicized incident earlier in the year.

As part of consideration of a key spending bill, one House member offered an amendment designed to changed a provision of the Patriot Act, the law Congress approved following the September 11, 2001 terrorist attacks providing law enforcement agencies with sweeping new powers.

House rules provide only that roll call votes be held open for a minimum of 15 minutes, a standard usually adhered to. But a majority party, facing possible defeat and defections by its own members, can hold votes open for longer.

Such was the case with the amendment offered by Congressman Bernie Sanders, a fiery Vermont Independent, whose proposal attracted considerable support from Republican House members.

The amendment, opposed by the Republican leadership, would have prohibited the Justice Department, as part of efforts to detect potential terrorists, from reviewing records of people who use public libraries or bookstores.

Republican Congressman Jim Sensenbrenner urged defeat of the Sanders amendment. "I would submit to you that if you look at what this amendment proposes to get rid of, it gets rid of a procedure that grants more protection to book sellers and is of much narrower scope than of the alternative of the grand jury subpoena," he said.

By holding the vote open, key Republican leaders bought enough time to persuade Republicans tempted to vote with Democrats to switch from yes to no.

The presiding House officer, Republican Congressman Doc Hastings, read out the final vote, a victory for Republicans by the narrowest of margins. "On this vote, the yeas are 210, the neys are 210, one member voting present, the amendment is not agreed to."

Congressman Sanders had this response: "What kind of lesson are we showing the children of America, when we tell them get involved in the political process, that we are a free country, that we're fighting abroad for democracy, when we rig a vote on this floor? Shame, shame, shame!"

An outraged Congressman Steny Hoyer, number two Democrat in the House, accused Republicans of using the extension to arm twist dissenting Republicans. "If you campaigned on changing the tone in Washington. If your objective was to bring comity to this House. If your objective by voting for the Patriot Act was to protect democracy. Then protect it here. Protect it here in the people's house. Protect it here where every one of you has an opportunity say we will have a fair vote, in a fair timeframe and the majority will prevail, not the intimidated will prevail.

The uproar in the House mirrored a similar instance in early 2004 when Republicans held open a major vote on legislation to reform the medicare drug system for more than three hours to gain a victory.

Republicans, such as Congressman David Dreier, justify the tactics by recalling similar methods Democrats used when they were in the majority. "The process which we [Republicans] observed on numerous occasions when my friend's [Democrat] party was in the majority was something that did provide an opportunity for us to learn from."

Whether business as usual as Republicans portray it, or undermining of legislative civility as Democrats contend, the partisan squabbling follows the end of an informal truce between the parties on filing formal complaints over alleged violations of congressional ethics, and comes amid a sharp rise in political skirmishes as the 108th Congress approaches the end of its second session and final session on the road to the presidential election in November.