The Washington Civic Center, a proposal resurrected from the congressional slag heap earlier this year, has become a focal point of activity this summer for city officials scrambling to prove its financial worth and detractors seeking to scuttle the project by referendum.

The proposal was given a second life through an agreement between a Vermont senator who thinks construction of the controversial $110 million complex is a "lousy idea" and a Kentucky congressman who supported this project even though he was instrumental in killing a similar one several years ago. Both chair congressional subcommittees that must approve the project.

Center supporters see it as an enormous boon to the city, annually attracting between 310,000 and 390,000 new convention visitors to the city and boosting city tax revenues by $12 million a year.

Opponents say the project would benefit only the private business sector and produce an annual net loss by between $6 million and $9 million, which the city would have to pay.Various civic groups are in the forefront of the opposition and are trying to force a vote on the issue by city residents. There is some doubt, however, about the legality of putting such a proposal, a capital budget item, on the ballot.

Given the conflicting estimates on the proposal, two congressional subcommittees added some conditions to their agreement. The major condition is that private developers must promise to build "spin-off" projects such as hotels, restaurants and stores in the civic center complex. The city now is busy trying to secure such promises before going before the subcommittees in September for a final decision on the project's first phase.

No developer has yet pledged to build a project specifically related to the civic center, which is to be located in a three-block area south of Mount Vernon Square and bounded by New York Avenue and H. 9th and 1th streets NW.

The nearest major hotels - such as the Madison, Capital Hilton, Mayflower and Hyatt Regency Washington - are several blocks from the center site. The large Shoreham Americana and Sheraton Park hotels are about two miles to the west.

Private developers are said to be cautious because they recall the proposed Eisenhower convention center suggested for the Mount Vernon Square area in the early 1970s. After months of controversy, the proposal was killed. Rep. William Natcher (D-Ky.), chairman of the House District Appropriations Subcommittee, who then favored a city referendum, led the opposition.

Natcher's subcommittee and the Senate District Appropriations Subcommittee chaired by Sen. Patrick Leahy (D-Vt.) must be convinced by District of Columbia officials of the center's financial viability. The officials must show that attendant private development will occur as a direct result of the center's construction and generate enough revenue for the center to break even in costs of three years after it opens.

If the center proposal clears congressional hurdles, the building could be operating by mid-1982, according to the city's current timetable. The project has the enthusiastic backing of Mayor Walter Washington, most members of the City Council and the hotel, realty, banking and retail groups associated with the powerful Metropolitan Washington Board of Trade.

In addition to attracting new visitors and new tax revenue, the center would help rejuvenate the aging downtown area and provide jobs for a needy and predominantly black community, the center's supporters say.

"The convention center is part of our whole economic strategy," said Ben W. Gilbert, director of the D.C. Municipal Planning Office and a central figure in the city's effort to build the center. "This is not just some wild idea that somebody in city hall got," he said.

Such views are not shared by more than 60 civic associations and neighborhood groups and some elected officials fighting the proposal.

Carol Gidley, representing Friendship Heights and American University Park in Advisory Neighborhood Commission 3-E, said city residents already are overtaxed and underserviced, a condition she feels would worsen if the center is built.

The financially hard-pressed city could find better uses for its money, she said, adding that citizens "have not been asked themselves whether they want it, and they're going to have to fund it for 30 years."

As a capital budget project, the $110 million center would be financed initially by borrowing from the U.S. Treasury, then refinanced at a lower interest rate when the city issues its own tax-exempt bonds. Fixed costs are expected to total $10.1 million a year, including a $500,000 operating deficit and a debt service of $9.6 million over 30 years.

Gilbert insisted that a successful civic center "can help take the tax burden off the people. Cities have not done enough in this way, and the center can help."

Sen. Leahy shares some of the opponents' concerns and thinks the proposals could be "a sleeper issue" in city elections this fall. His subcommittee voted last fall against including $27 million in initial funding for the center in the city's fiscal 1978 budget. Creating budget stalemate Leahy and his House counterpart, Natcher, who now supports the center, failed to compromise on the project.

Last May, Leahy, Natcher and city officials reached a budget agreement, including funds for the center, on condition that no money be spent until both subcommittees are satisfied the center will not become a financial burden on the city.

To assure the center's economic viability, Leahy directed the city to obtain enough specific private development committments to match in tax revenues the expected $10.1 million fixed yearly cost of the project.

As a third condition for budget approval, the city agreed to extend a surtax on corporate business and to impose an 80-cent tax on occupied hotel rooms to fund the years before the center is fully operational.

"Sen. Leahy has said he wants to be convinced," Gilbert said. "We've been told to do certain things, and we're going to give to it our best shot."

To "document" the center's expected success, Mayor Washington appointed City Administrator Julian Dugas to head a special task force responsible for meeting all requirements in the agreement. Several city agencies are assisting and a revised center proposal is not expected for at least a month.

Gilbert said the strongest opposition to the center "is coming from a relatively small group" of people "who haven't addressed the very premise of the convention center: that it is to be a tool of development that will create revenue for the city."

"What kind of a city do you want to have? Do you want it to be a live, vibrant place with a vigorous economy? Or do you want to live here just to do your job and not be bothered?" Gilbert asked.

Public hearings are scheduled next month, and groups opposing the center say that at previous public hearings the full City Council listened attentively to arguments by proponents in the business sector. Then, opponents say, all but the chairwoman of the hearing walked out as community representatives prepared to present their views.

According to Leahy, "a lot of people wanted a referendum" on the convention center issue and asked him to require it as a condition for approval.

"But that look like a cop-out," Leahy said. "There is no right on the part of Congress to direct a referendum on elected city officials."

"I think the convention center is a lousy idea, but I felt the city had a right to do it," he said. "My only concern then was, to what extend do we allow the use of federal funds for the project?

The few informal polls taken on the subject, including a constituent survey by D.C. Del. Walter Fauntroy (D) earlier this year, indicate that almost two-thirds of those polled oppose construction of the center.

A law effective in October will allow city residents to initiate referendum and recall petitions, which must be signed by 5 percent of voters from 5 of the city's 8 wards. If the required signatures are obtained, construction of the center would stop pending the election. There is uncertainty, however, about whether a capital budget item is subject to referendum.

The city's ability to show the subcommittees it can obtain private development commitments is important to approval of the center, but there may be considerable disagreement about what constitutes a bona fide civic center "spin-off" project.

News of possible approval of the center is causing "a whole resurgence of activity" in the old downtown area, according to Knox Banner, former head of Downtown Progress and now executive director of the city's Office of Business and Economic Development. He cited interest shown by developers in renovating the Willard Hotel that has stood vacant for 10 years at 14th Street and Pennsylvania Avenue NW.

Other city officials pointed to a hotel in the West End area planned by restaurateur Ulysses (Blackie) Auger and a major project announced for the downtown block where Garfinckel's is located.

"Nonsense," said a Leahy aide when asked if the subcommittee would consider such projects "spin-off" development.

The development has to occur "because the center is coming to town" and not because it would have been built anyway, the aide said, adding that projects about which the city has been talking had been announced or planned prior to the convention center compromise.

Banner said that about 30 acres of land in the convention center site area already are in packages "big enough to build on" and that his office hopes to have a better idea soon about specific projects.

Several center opponents, including Leahy, have questioned the estimates made in a consultant's study on the center. The study said the complex would attract a large number of new conventions and eventually make a profit if properly managed.

Planning director Gilbert, says the study's attendance and tax revenue projections "can stand up under scrutiny."

Initial plans for the center called for 300,000 square feet of exhibit space and about 80,000 square feet of meeting space. The new plan includes at least 250,000 square feet over-all, according to John Fondersmith, chief of special projects for the city planning office, who said anything smaller "would change the whole nature of the enterprise." Some competing centers are much larger, he said, and could better accommodate larger conventions and trade shows.

Len Hickman, executive vice president of the Washington Hotel Association, said the new 80-cent tax on occupied rooms "is putting out hotels in a slightly less competitive situation." But he stressed that association members are earger to "prove Sen. Leahy that the c enter will not be a drain on the city's economy . . . and we need the center to stay competitive. Every year the convention groups get bigger and bigger."

Mayor Washington, City Council chairman Sterling Tucker and at-large Council member Marion Barry - all mayoral candidates - hope the center will improve the city's employment situation.

"When we talk about jobs for the city's unemployed, we're talking about people who are mostly black," Barry said. "It is generally a lot of white people - and I don't like to use race - who say we shouldn't build the center. But where else are we going to find so many jobs for D.C. people in the private sector?"

The consultants' report estimated the center would provide from 2,000 to 4,000 permanent new jobs, but the figure has been questioned by project opponents.

Advisory neighborhood commissoner Gidley noted that one opposition group is the prodominantly black Federation of Civic Associations that represents 53 community organizations throughout the city.

Because construction money is to come from the capital budget, Gidley and others warn about a possible shortage of funds for sewer treatment projects and schools.

But Gilbert noted:

"We're not looking at the convention center as a public utility or an institution but as a method of providing support for a very important industry here, the tourist and convention business."

Answering "sure," when asked if his subcommittee might still reject the center project, Leahy said: "We'll review whatever comes back to us.

"But if everybody is working hard on the compromise, it will be okay with us at least from a fiscal point of view. And the taxpayers can be happy with that," he said.