COLUMBIA, S.C., MARCH 12 -- Jesse L. Jackson rode a tidal wave of support in his home state to win a decisive victory tonight in the battle for South Carolina's 44 convention delegates, swamping his nearest competitor, Sen. Albert Gore Jr. (Tenn.), by three to one.

With 93 percent of the Democratic caucus results in, Jackson won a majority, 54 percent. Gore had 18 percent, Massachusetts Gov. Michael S. Dukakis 7 percent and Rep. Richard A. Gephardt (Mo.) 2 percent. Another 19 percent of the estimated 45,000 caucus-goers -- a record turnout -- declared themselves uncommitted.

"Just because you are born in the slums, it doesn't mean the slum is borne in you," Jackson said tonight in Greenville. "I came to tell America there is a way out."

In black precincts, Jackson backers showed up in numbers that crushed any opposition. In many urban, white precincts, Jackson got a significant number of votes. Of the first 21 of the state's 46 counties to report results, Jackson held a plurality in 18, Gore in two, and they tied in one county.

The results were not only a major victory for Jackson, who more than doubled the 25 percent he got here in 1984, but also were a setback for Gore, who had hoped to get a strong enough showing here to maintain the momentum he received from the "Super Tuesday" results on March 8.

"It's a slam-dunk night," John Harper, a Jackson campaign leader, said at Richland County Democratic headquarters.

"This shows Jackson is a viable candidate," said Kevin Gray, his South Carolina manager, stressing the high level of support Jackson received in affluent white precincts.

Today's victory could give Jackson a boost going into Tuesday's primary in Illinois, where he now makes his home.

In such white communities as Hampton Hills, Shandon, Rosewood and Forest Hills, Jackson either won a plurality or held even with his white competitors. The results, however, not only reflect white support, but also the extraordinary growth in urban areas of the Republican Party, which turned out 185,000 voters for its primary a week ago. This growth has left a Democratic core of white liberals and blacks, the two groups who tend to dominate caucuses in areas like Columbia and Charleston.

Perhaps more than in any other southern state, the Democratic Party here has lost its grip on white voters, including the textile workers who once formed the backbone of the party.

John Jameson, Gore's southern regional coordinator, said, "It's been a good night for Gore. It's a strong second in Jesse's home state."

He argued that Gore will do well when delegates elected today meet later this month at congressional district conventions and many of the uncommitted decide among the competing candidates as they choose delegates to a state convention, which will name the 44 national delegates.

Don Fowler, former state Democratic chairman, estimated that Jackson could get 30 of the 44 delegates, Gore 12, with the other two uncommitted.

For Gore, the results provide no boost to carry him through the rest of what is likely to be a tough month. Gore, who did well on Super Tuesday by campaigning as a regional favorite in the South, faces a series of northern or midwestern primaries and caucuses, including Illinois, Michigan and Connecticut. In April, the situation could worsen for Gore, with primaries in New York, Wisconsin and Pennsylvania -- all considered favorable to front-runner Dukakis, who leads with 460.5 national delegates to 400.5 for Jackson.

Gore and Jackson campaigned heavily here with their families. On the campaign trail, Jackson generated far more enthusiasm than any of his competitors, and touched a still-raw nerve is this Deep South state when he declared: "The hands that picked cotton in 1965 can pick a next president in 1988."

Gore, who in the days before Super Tuesday began to voice populist appeals, reiterated his stated goal "to put the White House back on the side of the working man and woman." And he repeatedly cited his support for textile legislation vetoed as protectionist by President Reagan. The textile industry is a significant factor in South Carolina's economy.

Under the caucus system here, any of the state's nearly 1.3 million registered voters willing to declare allegiance to the Democratic Party was eligible to attend one of the 1,788 precinct caucuses.