Once there was unity in Prince George's.

For 10 years, members of the local delegation belonged to what was considered the most disciplined and powerful Democratic organization in the state. Year after year they marched in virtual lockstep to Annapolis and brought home generous state aid, high-level appointments and legislative victories.

But this year, as their genteel Montgomery counterparts have begun to band together for mutual comfort and financial support, the celebrated Prince George's ticket is falling apart. Members of the old organization are going their separate ways, with individual fund-raisers, offices and literature. For many, it is a first in their political lives.

"There's no real theme," said Thomas V. (Mike) Miller, chairman of the Prince George's senators. "We're all talking about how the Democrats are going to be together, and get literature together and stuff, but there's no platform. We used to have a preamble, a platform, a policy committee, a campaign committee. There's not going to be any of that this year at all."

The politicians offer various reasons for the change: public criticism of the old slate as exclusionary, lack of a leadership, and a charter change which forces all county council members to run from districts, making the old top-to-bottom slate less economical. Besides, said former slate campaign manager John McDonough, "Nobody feels like doing it. It's hard to do. It requires people to yell at you; there's fights."

Even this year's minimal effort at consensus, a move by the senators to produce a common piece of literature, erupted into battles over which candidates for House of Delegates could run with "the team," which candidates for higher office would be pictured, and who was going to make the decisions.

Whatever the reasons, candidates agree that this election year already is forcing them to walk a tightrope between friends and allies who may be running against each other, a particular problem for Fifth District Congressman Steny Hoyer. Hoyer, a former state senate president and a leader of the old Democratic organization, still is considered a local mentor whose blessing is eagerly sought by candidates.

Divided loyalties forced Hoyer to to attend the fundraisers of opposing candidates, both his friends, on consecutive evenings last month. He read a carefully worded statement at both events, that "used every word except the word 'endorse,' " said one of the candidates, Andrew O. (Sonny) Mothershead, who is running for a Beltsville area state senate seat against incumbent Arthur Dorman. "But everybody felt he endorsed me," he added.

Along with their concern about the increased cost of campaigning individually, advocates of the old slate method worry about the enhanced influence of interest groups as candidates scramble for campaign dollars. For the first time, for example, the county's Chamber of Commerce has formed a bipartisan political action committee, dubbed Bus-Pac, to contribute to candidates with a probusiness slant. And representatives of the Metropolitan area AFL-CIO have begun announcing their endorsements at breakfasts at the Capital Centre, to impress the media with the potential electoral impact of their 65,000 members in Prince George's.

The irony of election year 1982, said McDonough, "is that the one thing everybody predicted you'd have, you don't have -- the wave of people traditionally not involved in Democratic politics running for office. That's been almost nil." Among the few hotly contested seats in Prince George's, the challengers are mostly former slatemates giving vent to old rivalries. Similarly, very few Republicans have made any attempt to run for office this year. For 31 seats available to Prince George's in the General Assembly, only 14 Republicans have filed, five of them from the new, shared Prince George's-Howard County district.

Black candidates, most of them hoping to represent the middle-class homeowners east of the Beltway, are the exception. Half a dozen newcomers from both parties have begun campaigns to increase the level of black representation in a county which is close to 40 percent black but which sent only three blacks (out of 32 seats) to the General Assembly this term.

Political intrigues notwithstanding, legislators face some serious issues in Annapolis in 1983 -- like severe overcrowding in the state's prisons, and what some consider a duplicative, overextended university system -- of which many voters may be unaware, legislators say.

"What do people always worry about? Crime, taxes and schools," said Del. Timothy S. Maloney. "But what does the legislature have to deal with? Prisons, colleges and serious deficits in mass transit. But if they have to start paying astronomical property taxes to support a patchwork higher education system, they may start to care."

Legislators may also be expected to take a stand for or against the modification of TRIM, a controversial 1980 charter amendment which limits the amount of revenue the county can collect from property taxes. Though it is not strictly a state issue, many county voters are concerned about cutbacks in school spending that forced teacher layoffs this year. Though many county officials have warned that all county services will suffer if TRIM isn't amended, county executive Lawrence Hogan and other Republicans have denied that a problem exists.

With the proposal to modify TRIM on the ballot this fall, legislators will likely be asked their views. And those who are elected will be pressured to bring home more aid from Annapolis to bail out county services, regardless of how Prince Georgians vote on TRIM.