Leaders of the General Assembly began an effort today to resurrect public financing of political campaigns in Maryland, which in the past five years has seen state taxpayers funnel more than a half-million dollars into a campaign funding account that has never been used.

At a State House press conference, three powerful legislators and a cadre of public interest lobbyists announced they had persuaded 47 House members and a majority of the Senate's leadership to sponsor a new bill that would create public financing of campaigns for governor, lieutenant governor, attorney general and comptroller in 1982.

Since the original public financing law was passed in 1974, state citizens have been able to donate money by making notations on their annual income tax forms. According to state tax records, 268,000 Maryland taxpayers have contributed $536,254 to the fund. But not a dime of it has gone to its expressed use because supporters of the concept have lost every legislative attempt to implement the measure in the last five years.

Opponents of public financing -- most notably a single Baltimore delegate, Paul Weisengoff -- have managed to postpone the effective date of the law for two elections. Meanwhile the funding provisions of the 1974 plan have proved to be ineffective, and every attempt to improve them has been halted by Weisengoff and his allies -- sometimes by extraordinary means.

After particularly stinging defeats in 1977 and 1978, public financing supporters left the issue largely untouched last year as the legislature concentrated on tax returns and a new ethics law. This year, they say, is their last chance to repair the law -- and spend the money that has been collected -- before the 1982 election.

"Either public financing is going to pass this year, and the money will be used," said Del. Gerard F. Devlin (D-Prince George's), one of the sponsors of the bill, "or the measure will fail again and the whole public financing concept will probably be repealed."

Indeed, the repeal of public financing and the death of the idea once and for all is exactly the goal this session of Weisengoff, who was originally persuaded to support the idea in 1974. "I think it's a bad idea and I'm going to try to kill it," he said gleefully today as the new bill was being unveiled. "It's an old idea that has proved to be unworkable."

The new campaign financing bill is in part an effort to diffuse pass legislative opposition by cutting back on the original system. It eliminates, for example, financing for the campaigns of state delegates and senators, thus removing the objections of legislators who thought such funding was against their own reelection interests.

The bill would provide matching funds for candidates who run for the four highest state offices in primary elections, and all the funds for general election campaigns. It would limit the total amount that could be spent by any one candidate to less than $600,000 in the governor's race and to lesser the amounts in the other races.

Most importantly, the bill would mandate that any funds needed for financing the campaigns that do not come voluntarily from taxpayers would be made up by special budget appropriation. The 1974 law has no such provision, and thus has not raised enough money for public financing to take effect.

The bill's supporters have collected imposing lists of sponsors for the new plan, including Senate President James Clark (D-Howard County), Majority Leader Rosalie Abrams (D-Baltimore City) and a majority of the membership of the House Constitutional and Administrative Law committee, one of two House panels that will consider the bill.

Although the measure does not have the official endorsement of the House leadership, House Speaker Benjamin L. Cardin (D-Baltimore City) and Majority Leader Donald Robertson (D-Montgomery) have long been among the foremost supporters of public financing.

This measure is favored to pass the Senate, which approved a nearly identical measure in 1978. In the House, however, the bill's sponsors admit they have an uphill battle against Weisengoff, who sits on the second committee to hear the bill, Ways and Means, and has never been deterred by the opposition of Cardin and Robertson.

In 1977, for example, Weisengoff managed to stop public financing even from reaching the House floor by drawing up an unpredented petition to keep it in committee and persuading 74 of the 141 House members to sign it.

"Didn't we do a job on that bill last time?" Weisengoff exclaimed today. "We'll find some way to stop it this year, too."