Democrats: Candidates again argue that the proposal favors the rich. Brown and Clinton engage in heated exchange over civil rights.

In a debate notable for its restrained tone, the four remaining major Democratic presidential candidates argued about economics and civil rights Thursday night as they angled for support in next week’s Super Tuesday primaries.

Former Massachusetts Sen. Paul E. Tsongas came under attack for his economic plan, which includes a capital gains tax cut and investment incentives. His rivals branded the proposal “trickle down” economics, as they have done in previous encounters and on the campaign trail.

“That’s exactly what we did in the 1980s and the economy went downhill and it’s wrong,” Arkansas Gov. Bill Clinton said. “Average wages went down, the workweek lengthened, poverty exploded and we lost our competitive edge.

“Put people first,” Clinton said.

Iowa Sen. Tom Harkin, whose campaign is nearly broke and could end if he does not do well Saturday in South Carolina, echoed Clinton’s criticism.

“That’s really trickle down,” Harkin said.

Tsongas stuck by his proposals, however, saying the wealthy would pay for his capital gains tax break and that the venture capital created would help businesses. “There is an inevitability to what happens if you don’t invest,” Tsongas said.

But the liveliest exchange of the night occurred when former California Gov. Edmund G. (Jerry) Brown Jr. attacked Clinton for failing to pass a civil rights law in his state. Arkansas and Alabama are the only states without one.

Then Brown asked Clinton about a recent newspaper photo of him and Georgia Sen. Sam Nunn at a prison-like boot camp in front of a group of black prisoners. Clinton and Nunn “looked like colonial masters,” Brown said, and the prisoners “looked like a bunch of Willie Hortons”--a reference to a black Massachusetts murderer who President Bush used against 1988 nominee Michael S. Dukakis to great effect.

“I want to know what kind of message were you trying to send?” Brown said.

Clinton, whose candidacy relies heavily on the backing of black leaders and voters, turned to Brown and glared. He had tried to pass a state law, he said, but at the request of black legislators had formed a commission to draft a tougher version.

“Jerry, chill out, you’re from California, chill out,” Clinton said. “Nobody has a better civil rights record than I have.”

He visited the prison, Clinton said, because it offered an experimental “boot camp” program for first offenders as an alternative to the state penitentiary. “This is the kind of thing I believe in,” he said. “I went there because that represents the kind of program I want to support.”

The death penalty, a hot topic in the South where many of the Super Tuesday contests will be held, was also an issue. Harkin criticized Clinton for supporting capital punishment, which is opposed by most civil rights leaders. The law is enforced arbitrarily, he said.

“For example, the killer of Martin Luther King is still alive,” Harkin said. “The killer of Robert Kennedy is still alive. . . . And yet recently Gov. Clinton’s own state executed a man who killed a policeman, a heinous crime to be sure, but he then turned the gun on himself and half blew his brains out. And yet the state of Arkansas executed this man. What kind of justice is that?”

Clinton noted that three men were executed during his tenure--two white, one black--and called for more ways to prevent crime. “Thirty years ago, there were three policemen for every violent crime,” he said. “Now there are three violent crimes for every policeman.”

Tsongas said he supports the death penalty for “crimes against society”--such as major drug dealers--but opposes it for crimes against individuals because “eventually we are going to execute someone who is innocent.”

Brown said he is morally opposed to the death penalty in all instances.

The economic differences between Clinton and Tsongas were one of the major themes of the evening. Tsongas said the United States suffered because, unlike Japan and Germany, it did not have an economic strategy.

“You walk out in the street and ask anybody what is George Bush’s economic strategy to rescue this country and they cannot tell you,” he said.

Citing a Massachusetts Institute of Technology study of the loss of manufacturing jobs as a rationale for his proposed capital gains tax cut, Tsongas said: “The conclusion of the report was that to live well you must produce. Ultimately, you have to invest in the infrastructure, the manufacturing base, the engine that drives the economy.”

But Clinton said Tsongas’ plan for a broad capital gains tax cut was too much like the Reagan-Bush policies he said cost 2 million manufacturing jobs and directed 60% of the income gains in the last decade to the richest 1% of the population.

Clinton also defended his support for a middle-class income tax cut and criticized Tsongas for opposing it, saying that Tsongas wants to delay economic fairness in the interest of economic growth.

Harkin, a traditional liberal, urged defense cuts and more federal spending on the infrastructure to combat unemployment.

And Brown reiterated his call for a 13% flat tax that would replace the entire federal tax system, including income, corporate, estate, gift and gas taxes as well as Social Security. Under Brown’s plan, the only deductions would be for mortgage interest, rent and charitable contributions.

Brown and his proposals came in for more attention and criticism than in earlier debates--probably because his surprise victory in Colorado has given him credibility and forced his rivals to take him seriously. Clinton suggested that Brown’s plan would actually result in a tax increase for many Americans. Brown insisted that it would not because it would replace all other levies.

And, as he has done before, Brown criticized his rivals for accepting campaign contributions up to the legal limit of $1,000 from individuals, when he himself takes no more than $100 from anyone. Harkin complained about Brown’s constant stress on campaign contributions as the root of all political evil and reminded Brown of his past fund-raising practices, including his recent stint as chairman of the California Democratic Party.

“Now he sits there and sort of in a self-righteous manner paints us all in one brush,” Harkin said.

The taping of the 90-minute debate, moderated by ABC News anchorman Peter Jennings and shown in the “Nightline” time slot, was delayed for nearly an hour because of a dispute over the format. According to Harkin campaign officials, ABC News presented the candidates with a plan that relied on having the candidates question each other instead of having Jennings ask the questions.

The candidates rejected this. Finally, the debate took place using the traditional format--Jennings asked the questions.

On Super Tuesday, 11 states with 783 delegates will be at stake. The biggest prize is Texas, with 196. The following Tuesday, March 17, the candidates will battle each other in Illinois, for 164 delegates, and Michigan, for 131. Three weeks later, on April 7, 244 delegates will be up for grabs in New York, along with 82 in Wisconsin and 36 in Kansas.

Political writer Cathleen Decker in Dallas contributed to this story.