Nothing like it has happened since pre-Civil War days - but the incident left an unforgettable blot. On May 19, 1856, Sen. Charles Sumner of Massachusetts delivered a powerful speech condemning the South for national unrest. Sumner directed his remarks at an elderly South Carolina colleague, Sen. Andrew Pickens Butler. Reflecting the intemperance of those times, he suggested that Butler had chosen "the harlot, slavery," as his "mistress."

Three days later Butler's nephew, Rep. Preston Brooks, D-S.C., strode into the Senate chamber brandishing a heavy gutta-percha cane. Sen. Sumner was at his desk writing when Brooks approached. As he looked up, Brooks brought the cane down on Sumner's bare head. With the senator's long legs tangled underneath a desk that was fastened to the floor, his agonized struggle to rise tore the desk loose. As Sumner fell onto his back, Brooks continued to batter the man's skull until the cane broke.

Contemporary reports described Southern senators nearby as failing to intervene - some even smiling at what they saw. Sumner's injuries disabled him for three years, almost blinding one eye. But "Bully" Brooks became a Southern hero. He received scores of canes, plus a gold-handled cowhide whip intended for use on other abolitionists. And a Washington magistrate dismissed what could have been an attempted murder charge, letting the congressman off with a $300 fine.

Then, as now, members of either house are permitted access to the opposite chamber without challenge - a custom rooted, I suppose, in a small-D democratic reliance on equality and trust. Excluded from official exchanges is any reference to an "upper" or "lower" house. Senators and representatives receive the same salary. One overwhelming difference, of course, is that the House member holds a seat for two years at a time, while a senator is comfortably ensconced for six.

Beyond this, of course, is the Senate's exclusive role in such matters as confirming executive department appointees and the judiciary, treaty ratification and the Senate's designation as a court of impeachment. Such tasks inevitably have added luster to the now 100-member body originally patterned on Britain's House of Lords, vis-a-vis 435 relatively lost souls in the adjoining chamber. It was not by chance that the U.S. Senate achieved recognition as "the greatest deliberative body on Earth."

And while I shrink from comparisons that might seem odious, it may be noted that House members often announce their departure to run for the Senate. Yet only one ex-senator of my memory sought and won election to the House - Florida's late Claude Pepper.

Often at loggerheads, the two houses remain unfailingly polite. House Rule XIV discourages references to the Senate except as "the other body." While it's OK to describe Senate actions in a neutral way, critical comment targeting individual senators is out of order.

The Senate has no written rule on comity, leaving matters of deportment to what it assumes to be the gentlemanly inclination of its individual members.

All of the forgoing serves as groundwork for an interesting development of recent days - a possibly short-lived role reversal in our national legislature. Distinguished orators of the U.S. Senate (aka The Greatest Deliberative Body on Earth) found themselves temporarily immobilized - silenced because leaders couldn't agree on how to debate the most important issue facing us today: the Iraq war. Meanwhile, the hitherto faceless House of Representatives not only debated the war, but passed a resolution aimed at ending it.

The familiar five-minute limitation on House speeches enabled nearly 400 members to be heard during the week's discussion - an interesting contrast to unlimited talk prevailing in that "other body."

Some of the Senate's full-throated orators - including its customary cadre of presidential aspirants - might view the five-minute House rule with scorn. In which case - well, let's acknowledge that a number of past messages that we all think important were conveyed within an equivalent time frame. Lincoln's Gettysburg Address consumed little more than three minutes. Patrick Henry's challenge to the Virginia House of Burgesses, climaxing in his unforgettable "Give me liberty or give me death," fell narrowly within five minutes. Thomas Gray's "Elegy Written in a Country Churchyard" qualifies - as does each and every Shakespearean soliloquy.

And don't overlook Gen. Anthony McAuliffe's terse but memorable response to the Germans' surrender demand at Bastogne: "Nuts," he said - remember?

That corresponds roughly to what voters were saying about the Iraq war in November's election - a message the House of Representatives has obligingly relayed to this administration.

And as for the once Greatest Deliberative Body on Earth - Ha!