When Sen. Joseph R. Biden Jr. scolds, fellow Democrats listen.

For 2 1/2 years, at rubber-chicken dinners everywhere, they've sat in rapt attention as the energetic Delaware senator conveys the awful news: Their party has squandered its vision, misjudged the national character, wallowed in self-interest, waylaid its compassion, surrendered to the status quo.

No one is spared the lash -- not even Biden himself.

But, oh, how the audiences respond.

The Speech has won Biden, 43, a reputation as one of his party's hottest orators, and lately it has set off a Biden-for-president boomlet, especially now that Massachusetts Sen. Edward M. Kennedy's decision not to run has thrown the Democratic field wide open.

It also puts Biden at the leading edge of his party's emerging Passion Wing, which surveys the Democratic firmament and concludes that what's wrong with Colorado Sen. Gary Hart and other "Atari Democrats" is their bloodlessness. What the party needs now, says Biden, is "real heart."

Nobody steps with such calculation on so many toes without collecting criticism. Biden's critics say you can't get to the White House on self-flagellation alone. They say his personality is too cynical, his delivery too shrill and his compassion too packaged to be credible.

And they say The Speech is dated. He was a voice in the wilderness when he first delivered it in 1983. But ever since their presidential election debacle of 1984, Democrats have been hearing nothing but diagnoses; what the party hungers for now, say the critics, are prescriptions.

Biden isn't of a mind to rush things. He says he won't lay out a policy agenda unless he becomes a candidate for president. He won't become a candidate unless his wife and three children consent, and unless the politics a year from now feel right. Meantime, he'll spend this year showcasing The Speech around the country, often with family in tow.

In a series of Jefferson-Jackson Day dinners in five states -- Virginia, New Hampshire, Oklahoma, Mississippi and Alabama -- Biden was the keynoter.

In a voice that can drip with indignation, ache with emotion or simply boom, he weaves these themes:

*The old Democratic orthodoxy led to paralysis -- and Biden does not exclude himself in the indictment. "We reached a point in the mid-'70s and early '80s when we forgot we had to constantly move on. And, after 50 years of success, we stepped back and gazed with a paralyzing self-satisfaction at our handiwork . . . . We said, 'Don't change anything. If you attempt to alter housing programs, you are not a true liberal. If you attempt to alter the progress of civil rights, you are questionable. If you doubt the wisdom of anything we have done, you are not a true Democrat.' And the cost to us was more than victory. It was our vitality. The Democratic Party became a fossilized shadow of its former self."

*The new Democratic solutions too often lack compassion. "How many of you in Concord felt the humiliation of the steelworker in Pittsburgh or the coal miner in Scranton when his work stopped and his dreams for his children collapsed? And how many of you in Portsmouth felt the desperation of the Delaware auto worker at the Chrysler plant as they closed the gate? And how many of you right here in Manchester felt or understood the numbness of the Iowa farmer as he watched an auctioneer sell off the land that had been in his family for three generations? And how many of you . . . sat smugly . . . when New York City had its problems and said, 'So be it.' We sat there and said, in New Hampshire and in Delaware: 'We have done all we can do. That's their problem.' "

*The path to salvation lies in reconnecting with old heroes, old values, the spirit of the '60s, the decency of the voter. "I am a member of the baby boom generation . . . and the cynics tell us that having reached the conservative age of mortgage payments, pediatricians' bills and saving for our childrens' education, we are ripe for Republican picking. Well, let me tell you folks, they have misjudged us . . . . "

Biden quotes from John and Robert F. Kennedy and the Rev. Martin Luther King Jr. and declares: "They made me reach beyond myself. They made me feel good about myself and my party . . . . And I think it's time for us as Democrats to touch the soul of the country again. And to challenge it. Not be afraid of it. Lift it up, with a soaring and singing sensation. The sunrise of a new day. My fellow Democrats, it's time to restore America's hope again, time to be on the march again. Put very simply, it's time to get America moving again. Let us begin. Our time has come."

Often The Speech brings tears. Here, however, the effect was less potent. Partly because of a bad sound system, Biden said, and partly because he tried to put too much oomph into the delivery, he shouted his way through. Many in the audience said they were moved, but others were critical.

"Why are you so mad at us?" one woman asked Biden at the reception afterward.

"It was an angry speech, and it made me uncomfortable," said Jeff Stover, a party activist. "Why does he lay the rap on us? Why not go after Republicans?"

"I kept waiting to hear what he believed in," said Wendy Klodt, who owns a small chain of women's apparel stores. "You'd think if he had time to tell some risque jokes at the beginning, he could get around to telling us that, too."

Biden maintains that he must touch the voters' souls first, then provide policy specifics. President Reagan "has appealed at the level of values" and put policy second, Biden said, while Democrats have gone at it the other way around.

He also insists that the self-criticism must continue. His close friend and adviser, Democratic pollster Patrick Caddell, agrees.

"Joe and I both take the approach: first on your knees, then salvation," Caddell said. "You've got to sting people first. You've got to move them and touch their consciences."

Biden and Caddell have been friends for 14 years. "Sometimes it's hard to know where Pat's thinking stops and mine begins," Biden said. In late 1983, Caddell urged Biden to run against Reagan and he nearly did, backing out at the last minute.

Last year, when Caddell's partnership with Democratic consultants David Doak and Robert Shrum was on the verge of dissolving, they called Biden in as mediator. He presided over hours of meetings; they split up anyway. But all three remain close to Biden, and presumably would be involved in a presidential bid, along with Boston consultant John Martilla.

Meantime, Biden enjoys a relatively clean slate. His Senate record has not been long on legislative accomplishment. His votes have tended to be liberal, but not in a knee-jerk way. It is a record with enough wiggle room to be offered to the public in just about any way he chooses.

And someday he may choose. But first, the lash.