The Senate's only black member, Carol Moseley Braun, made the chamber listen today as freshmen seldom do. Her oratory of impassioned tears and shouts, stopped Jesse Helms in his tracks as he defended the Confederate flag.

Senator Helms, the 20-year North Carolina Republican, had sought -- and seemed to be finding -- a roundabout way to preserve the design patent held by United Daughters of the Confederacy on a symbol that includes the flag.

He proposed language to that effect as an amendment to the national service bill, which would provide educational grants in return for various forms of service. With many senators unaware of what they were voting on, he won a test vote, 52 to 48.

Then Senator Moseley Braun, a freshman from Illinois, took the floor in outrage at the defense of a symbol of slavery. She told the Senate:

"On this issue there can be no consensus. It is an outrage. It is an insult.

"It is absolutely unacceptable to me and to millions of Americans, black or white, that we would put the imprimatur of the United States Senate on a symbol of this kind of idea."

As word of the debate spread through Senate offices, more and more senators came to the floor, most taking her side. Some disagreed, like Senator Mitch McConnell, Republican of Kentucky, who said "the Civil War is history." And Senator Robert C. Byrd, Democrat of West Virginia, insisted "The Confederacy is a part of American history." Speeches Rarely Sway

But they lost. The Senate, which calls itself the world's greatest deliberative body but in fact finds its votes changed sometime by public opinion but hardly ever by speeches, was convinced by the argument that the flag was an insult and killed the Helms amendment 75 to 25, as 27 senators changed their votes over three hours.

Senator Helms angrily insisted that his proposal had nothing to do with race or with slavery. "Race should never have been introduced," he said. "It is a political ploy."

He maintained that the symbol, a laurel wreath encircling the national flag of the Confederacy -- not the battle flag or stars and bars -- was instead just a proud insignia of a charitable group of "about 24,000 ladies of the United Daughters of the Confederacy, most of them elderly, all of them gentle souls who meet together and work together as unpaid volunteers at veterans hospitals."

Design patents like the Daughters of the Confederacy logo come up for renewal every 14 years. Most patents are simply allowed to lapse. But the Daughters of the Confederacy have gone to Congress for renewal four times this century. Renewal by Congress confers honor and prestige for certain patriotic groups; in fact, only about 10 groups, including the American Legion, have won patents from Congress since 1900.

Senator Helms said a decision of the Judiciary Committee on May 6 not to renew the patent on the organization's design must have been "a misunderstanding."

Senator Moseley Braun, who had led the committee effort against the extension, disagreed, but softly, complaining that the amendment was irrelevant to the national service bill.

So the first vote went ahead, as senators dashed in from lunch and hurried off to committee meetings. Senator Robert F. Bennett, a Republican freshman from Utah, told the Senate later that he "didn't have the slightest idea what this was about" but that he had joined instinctively in an effort to keep Democrats from killing a Republican amendment.

Mr. Bennett later offered the motion that enabled the Senate to reverse itself on the issue.

Then Ms. Moseley Braun returned to the attack, angrily. She said "This flag is the real flag of the Confederacy."

She said it symbolized the Civil War, "fought to try to preserve our nation, to keep the states from separating themselves over the issue of whether or not my ancestors could be held as property, as chattel, as objects of trade and commerce in this country.

"This is no small matter," she said. "This is not a matter of little old ladies walking around doing good deeds. There is no reason why these little old ladies cannot do good deeds anyway. If they choose to wave the Confederate flag, that certainly is their right."