An article in Monday's Washington Post, based on information supplied by the Federal Election Commission, incorrectly reported that Rep. Robert L. Livingston (R-La.) spent $1.3 million in his 1978 reelection campaign. Livingston says the $1.3 million figure includes $975,700 that he raised for a special election in 1977 and the FEC incorrectly reported as raised in 1978.

An embarrassing thing happened to Donald Stewart on his way to waging a grass-roots "people's campaign" for the U.S. Senate.

He found himself financing his campaign largely out of his own pocket and with contributions from special interest groups.

All told, the now Sen. Stewart, a young Anniston, Ala., lawyer of only modest means, borrowed more than $239,800 to keep his candidacy afloat and accepted $164,300 from special interest groups, including $12,655 after the election.

Stewart's situation isn't unusual. For the harsh realities of the 1978 election were:

Spending skyrocketed. The average Senate seat cost $1,058,671 to win in 1978, compared to $552,423 in 1974, the last nonpresidential year. Taken another way, the price tag on a U.S. senator rose almost three times as fast as the price tag on a quart of milk in that period.

The average House candidate, winner or loser, spent $108,000 in 1978, up from $71,000 two years before. The year saw the first million-dollar House campaigns.Carter Burden, a silk stocking Democrat, spent $1.4 million, or $20 a vote, in a losing bid in Manhattan. Rep. Robert L. Livingston, a Republican, spent $1.3 million to win in New Orleans.

Campaigns grew longer. Drawing upon the success of Jimmy Carter in the 1976 presidential race, would-be congressmen and would-be senators around the country began campaigning full time a year or more before the election. Stewart began in the summer of 1977.

Special interest influence grew.

The number of unions, corporations, trade associations and other groups with political action committees has more than tripled since 1974 to 1,700; their donations have risen almost threefold to an estimated $35 million last year.

One dollar out of every six the 20 new U.S. senators received in contributions last fall came from such special interests. One new senator -- William Armstrong, a Colorado Republican -- raised 43 percent of his campaign funds from such groups.

The Republican Party emerged as a major force in election financing. The party contributed $3.3 million to Senate candidates, or almost seven times as much as the Democratic Party. It contributed $2.6 million to House candidates, or almost five dollars for every one the Democrats gave.

Stewart was one of the political sleepers of 1978. A little-known state senator with a liberal reputation in a conservative state, he seemed an unlikely winner.

But by ignoring conventional political wisdom and doggedly crisscrossing the state, he built up a loyal band of followers. Trouble was, few had much money to contribute to his campaign.

Actually his seat (he is filling the last two years of the late Sen. James Allen's term) came relatively cheap. It cost $625,184, or about $220,000 below the national average.

The Senate spending leader was Sen. Jesse Helms, (R-N.C.), who spent $6.9 million, or more than $3 a vote to win a second term. Sen. Charles Percy (R-Ill.), spent $2.5 million, compared to $1.4 million during his last campaign in 1972. Sen. John Tower, (R-Tex.) spent $4.3 million, compared with $2.3 million in 1972.

Inflation, of course, accounts for much of the increase. A campaign button that cost 8 cents in 1972 cost 13 cents last fall; a 5-cent 1972 bumper sticker cost 8 cents in 1978.

But these increases, while they may seem high to politicians, are actually below increases in most consumer prices during the same period. Someone who spent $123 shopping at the neighborhood grocery in 1972, for instance, paid $168 for the same groceries in 1976, and $215 in 1978.

What really pushed the cost of the 1978 election through the roof were the jumps in fund-raising and television advertising costs.

For every dollar that Helms raised, 40 cents went to pay the cost of fundraising. Most of his money was collected by direct mail solicitations, according to his campaign staff director, Carter Wren. Federal campaign reporting requirements added to the costs. "We had to spend over $4,000 just to set up a bookeeping system," says Wren. "Then we had to hire two girls to do nothing but fill out forms full time."

Sen. Howard Baker (R-Tenn.) found television ad rates had increased 300 percent in Tennessee since his 1972 campaign. Percy found they jumped 600 percent in Illinois.

Stewart had to finance three separate campaigns in Alabama -- one for the Democratic primary, one for the runoff, and one for the general election.

He attracted little attention, and even less financial support until he forced Maryon Allen, the widow of the late Sen. Allen, into a runoff. By the Sept. 26 runoff, Stewart had borrowed $239,800, mortgaging almost everything he owned. Still he was outspent almost 3 to 1.

Normally, winning a Democratic runoff is tantamount to election in Alabama. But on Oct. 2, former Republican congressman Jim Martin, who previously had been running for the state's other open Senate seat, switched races.

Stewart suddenly was faced with a major, well-financed opponent with good connections in the state's business community. Seeing the possibility of winning a seat, the Republican Senate Campaign Committee pledged $230,000 to Martin. Special interest groups, chiefly corporate-related ones, kicked in another $59,523.

Stewart was faced with a dilemma.His own assets were stretched to the limit. The "fat cat" businessmen, whom he'd attacked earlier in the campaign while courting blacks and labor, weren't about to help him out.

He had little choice on where to turn. He went to special interest groups. His scored best with organized labor. Political action committees representing steelworkers, the AFLCIO, Seafarers and communication workers donated $5,000 each; the United Auto Workers kicked in $3,500; the American Federation of State, County and Municipal Employes, $4000; the National Education Association, the machinists, railway clerks each kicked in from $2,000 to $2,500.

The political arms of the American Medical Association, the trial attorneys, and the Automobile and Truck Dealers Association kicked in $5,000 each; those representing oil refining, savings and loan, and rural electrication interests each came up with from $2,000 to $2,500.

"I don't make any apologies for the money we received," Stewart now says. "We raised it the way we had to."

But he is extremely concerned about rising campaign costs. "It's gotten almost impossible for the average fella to get elected to the Senate without turning to special interests," he says. "I think that's bad for the country."

Stewart has hired a fund raiser to pay off his still large debt, and raise money for his reelection campaign only two years away.

He says he is going to refuse any more donations from special interest groups. "I'm not saying that money is bad. I know I took it and I don't feel any commitment to those that gave it," he says. "What bothers me is that money doesn't reflect individual participation or building a strong base. If you depend solely on special interests, you're cheating the system."