Cora Rice's first bid four years ago to win a Prince George's County Council seat could be summed up in the homemade, hand-lettered signs her artist son made for her campaign. Underfunded and little noticed, her primary campaign against incumbent Floyd Wilson was a classic underdog's fight.

But four years later Rice finds herself in a better position. With less than six months to go before Maryland's Democratic primary, the 59-year-old black community activist and council contender already has met with Baltimore Mayor William Donald Schaefer, the leading candidate for governor; Attorney General Stephen H. Sachs, the mayor's chief rival, and Baltimore County Executive Donald P. Hutchinson, a U.S. Senate candidate.

Said Rice of her new popularity: "It's a new day."

This is no ordinary election year in Maryland. Through a curious confluence of history and circumstance, Prince George's has become an unusually attractive place to look for votes this year and a wild card in the statewide Democratic primary on Sept. 9.

The fall elections promise the most dramatic shake-up in a generation of the state's top political leadership; a new governor, a new U.S. senator, at least three new representatives and several new county officials will come to power.

What make Prince George's particularly enticing to the candidates are its size and the lack of a sentimental "favorite son" -- or daughter -- running in the statewide races. As one of the largest jurisdictions in the state, the county delivers more than 200,000 votes in an average election, roughly 10 to 15 percent of the total.

Furthermore, unlike the Baltimore area, which is home to Schaefer, Sachs and three Democratic Senate candidates, no county politicians are on the statewide ballot this year, making Prince George's open terrain for vote-hungry politicians.

"Prince George's is clearly the prized political possession for 1986. It's the one area where everybody's got a shot," said Keith Haller, a Bethesda political consultant who has worked for Sachs and now has clients in Prince George's.

"I would describe us as a coy but not too reluctant maiden," said County Executive Parris Glendening.

So thick has been the political traffic through the county that the executive has taken the unusual step of assigning a staff member to act as liaison with each gubernatorial and Senate campaign.

"Hopefully we'll have a key influence," said Glendening. "Hopefully we'll become the swing vote with a large turnout and a large margin that'll put one candidate over the top."

But while statewide candidates look to Prince George's as a potential boon for their campaigns, the county's changing political landscape also makes it an unpredictable factor in the primary races.

Stimulated in part by Jesse Jackson's 1984 presidential bid, an emerging black vote has become a volatile force in the election.

Increasingly influential black political leaders such as Cora Rice, who again is challenging council member Wilson, have joined with disgruntled white activists to form a coalition that is threatening to dismantle the county's traditional Democratic Party organization, which has controlled Prince George's politics for two decades.

The coalition, buoyed by some of the 40,000 new voters who registered during the Jackson campaign, is openly competing with the long-term power brokers to see which side can deliver Prince George's for local campaigns and for their preferred candidates for governor and senator.

This old-versus-new battle for power in the county has left its imprint most clearly on the governor's race, where Schaefer has the support of the old organization and politicians such as Wilson, and where Sachs has allied himself with the new coalition and activists like Rice.

"When we talked to Mr. Schaefer, it was clear that he did not want to talk to us intelligently," Rice, a veteran member of the county branch of the NAACP, told a group of politically active black women after she met with the mayor a few weeks ago.

"Any questions that he was not comfortable with, he did not answer. And we determined that we, as black women, as mothers, as community leaders, cannot support someone for governor who will only be concerned with and who is only credited with a harbor. We don't have a harbor in Prince George's County. And we do not need a father. Someone who thinks that you relate to people as a father -- that we don't need," Rice declared.

By contrast, Sachs impressed Rice when he spent two hours discussing issues with her campaign committee at her Lanham home in January. And at a March 1 prayer breakfast at the Glenarden Town Hall, Sachs shared the head table with Rice, and, amid a crowd of 200 supporters eating eggs and humming gospel tunes, they formally endorsed each other.

Wilson, a pillar of the county's dominant Democratic organization who also hails from Rice's inside-the-Beltway, predominantly black Glenarden district, said he is likely to support Schaefer. He plans to do so, he said, because he identifies with Schaefer's economic development activities and record in local government, and "because it looks like Schaefer's going to be a winner."

"Rather than have members of the white community speak for us, I think it's time we go and cut deals on our own with his camp," said Wilson, displaying the trademark pragmatism of the county's incumbent black leadership. "My hope is that Schaefer will be sensitive to the needs of the county, and since he's going to win, I support him because it's politically expedient."

Wilson, 50, feels confident enough of his standing after three terms in office that he met with Schaefer two weeks ago to promote his availability for a lieutenant governorship, or at least a cabinet post. "I'm going to milk this as much as I can, to get as much as I can for black folks."

Sachs, on the other hand, said he is betting that Rice and her followers will become the political brokers for the next generation. "They are the future," he said. "It's a very natural alliance for me. My campaign and my whole political career has been characterized as a challenger to entrenched power."

He also took issue with state Sen. Thomas V. Mike Miller Jr., a longtime leader of the old Democratic organization, who has referred to Sachs' supporters in the county as dissidents and malcontents. "I think he's wrong about that," said Sachs. "And every time the vaunted Prince George's organization has been challenged by a credible candidate in recent years, the challengers have won."

Schaefer's campaign manager, Mark Wasserman, believes the mayor also has a market in the county. "I think Prince George's holds great significance for the mayor," he said. "There's plenty of good feeling between the city and P.G. -- we'll be going after it with lots of zeal when the times comes."

Although much of the current competition has centered on the governor's race, the Senate candidates have not ignored the county either: Donald Hutchinson has targeted Prince George's as part of his strategy for wooing rural areas and those with no favorite son or daughter.

Rep. Barbara A. Mikulski, a Baltimore Democrat running for the Senate, went to Prince George's for one of her five campaign announcements, and with visits to elected officials and activists has won the support of a cross-section of women, some blacks and, apparently, the old organization leaders. Miller, for one, likes Mikulski because "she's enthusiastic, she's feisty, she says what the people want to hear, and I truly believe we should have a woman on the statewide ticket."

Many black activists, particularly those associated with Jackson's Rainbow Coalition, have signed on with Rep. Michael D. Barnes, a Montgomery County Democrat also in the Senate race. Some like his association with the Washington area and the fact that he sought them out. He also is perceived as a successful fund-raiser who might help local races get off the ground.

Gov. Harry Hughes, who soon plans to enter the Senate race formally, has a list of local supporters, such as his campaign treasurer Fred Wineland, and held one of his first $1,000-a-plate fund-raisers in the county. He began a round of visits to elementary schools in Prince George's and played his trumpet at a widely publicized charity fund-raiser held in the county last weekend.

With the large number of candidates and the Prince George's political winds shifting so unpredictably, some observers speculate that the county's vote will be too divided to affect the outcome of the gubernatorial or Senate races.

"I don't consider Prince George's pivotal because I consider all the candidates qualified and people are going to support whoever they like," said Miller, a strong Schaefer supporter. "I don't think one group is going to be able to sell one particular group to any particular candidate."

To some degree, the outcome will hinge on the election day turnout, which in turn will depend in part on whether the county's significant bloc of unregistered voters can be persuaded to vote -- either by the traditional organization or by its challengers in the new coalition.

According to a recent state task force report, fewer than half of the county's eligible voters are registered to vote, a far smaller percentage than counties of comparable wealth and educational levels.

Both camps believe the untapped pool of unregistered voters could have a significant impact, particularly if any single candidate can persuade them to register and vote en masse for his or her campaign.

Secretary of State Lorraine Sheehan, a county resident who recently headed a task force on voter registration, summed it up: "If you can affect [the pool of unregistered voters]. . . you can make a big difference."