Without strong challenges to top incumbent officeholders in Maryland, the 1990 election was supposed to be a formal exercise with little bearing on the coming four years.

It hasn't turned out that way, though. State House leaders now expect the Nov. 6 general election to deliver strong signals from Maryland's 2.1 million registered voters about tax increases, growth and development, the involvement of special interests in politics and whether Republicans have moved the state closer to two-party status.

After the Sept. 11 primary ouster of four incumbent state senators, the November election for members of the General Assembly also will go a long way toward determining what restrictions, if any, the state will place on women's access to legal abortions.

Democratic Gov. William Donald Schaefer, who served 15 years as Baltimore's mayor, is conducting what some observers consider his last political campaign in a state that limits governors to two terms.

After a nonchalant primary campaign, Schaefer, 68, has returned to classic stumping this fall. He holds a more than 20 to 1 fund-raising edge and a wide lead in the latest independent polls. Yet, he appears unlikely to defeat Republican William S. Shepard, of Potomac, with the 82 percent of the vote he captured in 1986.

Shepard, 55, generated widespread criticism when he chose his wife to be his lieutenant governor running mate, and his campaign never recovered sufficiently to draw significant contributions and support.

In three of the state's most populous counties -- Montgomery, Anne Arundel and Baltimore -- dissatisfaction with rising property taxes took on the earmarks of revolt. If voters favor ballot questions that limit annual tax increases, as polls suggest, the message also will be felt in Annapolis. Early next year, lawmakers are expected to consider proposals to increase state income, sales and gasoline taxes.

The anti-growth tide that led to Montgomery County Executive Sidney Kramer's narrow Democratic primary defeat will be tested again Nov. 6. In an unusual move, Kramer is mounting a write-in campaign to defeat veteran County Council member Neal Potter in the executive's race. In Baltimore County, incumbent County Executive Dennis Rasmussen, a Democrat, faces a surprisingly strong challenge based largely on resentment against taxes and growth.

Though Democrats still hold a 2 to 1 edge in Maryland voter registration, Republicans viewed 1990 as a chance to cut into the Democrats' dominance in fast-growing suburban counties and in the 1st Congressional District.

After falling only 1,500 votes short of defeating Democratic Rep. Roy P. Dyson two years ago, Wayne Gilchrest prevailed in an eight-man Republican primary field in the 1st District and was tapped by the national party organization to get strong GOP attention heading into the November race.

Dyson has represented the district, which covers Southern Maryland and the Eastern Shore, for five terms. But he has been constantly on the defensive because of his close financial ties to special interests and questions about how his hawkish conservatism squares with his designation during the Vietnam War as a conscientious objector.

The other members of Congress from Maryland are heavily favored to win reelection.

In Anne Arundel County, Republicans hope to pick up the county executive's office. Former House of Delegates minority leader Robert R. Neall was considered the early front-runner against Democrat Theodore Sophocleus, but recent polls showed the race too close to call.

Republicans also hope to gain ground in the 188-member General Assembly, where the GOP held only 24 seats for the last four years. Some of their best opportunities, Republicans said, were in Howard, Montgomery, Baltimore and Carroll counties.

Among Democratic statewide officeholders, Comptroller Louis L. Goldstein faces Republican Larry M. Epstein, and Democratic Attorney General J. Joseph Curran Jr. is matched against Republican Edward L. Blanton Jr.

Abortion-rights advocates claim that the September primary assured them majority support in the state Senate and House, but they concede that the outcome of a handful for general election contests will determine what kind of concessions they must make to get a bill passed in the General Assembly next year.

In Howard County, few incumbents are finding it easy to rest on their laurels this year.

The county's long-dormant Republican Party is fielding several challengers in this year's races, all of whom are telling voters that if they don't like what has happened to the county, if they don't like the crowded schools and congested roads, they should blame the Democratic Party that has been in power all these years.

The Democratic incumbents, for their part, say voters are smart enough to recognize that current officeholders have been working to clean up the problems left by past administrations.

How their debate is playing is difficult to tell from the sparsely attended campaign forums that have been held so far.

The GOP challengers are led by Democrat-turned-Republican Charles I. Ecker, a retired school administrator who is making his first run for public office by taking on County Executive Elizabeth Bobo.

Ecker has promised to get civic leaders more involved in the business of government, while Bobo is running on her record of shepherding several major pieces of growth-control legislation through the County Council.

Joining Ecker is Dennis R. Schrader, a Columbia resident who is running for the County Council against Democrat Shane Pendergrass in District 1; Darrel E. Drown, a budget officer for the county's school system who is trying for a second time to defeat Democrat Angela Beltram in District 2; and Michael J. Deets, a Columbia Association Council member drafted by Republicans after the filing deadline to challenge Democrat Paul R. Farragut in District 4.

Democratic incumbents are not the only candidates facing competition. The County Council's only Republican, Charles C. Feaga, finds himself campaigning hard for the second time this election season. He narrowly turned back a primary challenge from Republican John Taylor. Now, he faces Susan Scheidt, a lifelong county resident who began her campaign by walking 32 miles across District 5 to meet voters.

Only council member C. Vernon Gray (D-District 3) faces no opposition this year. He has been making regular campaign appearances but says that "every public official should get a chance to enjoy a free ride at least once."