It's a year in Maryland politics that shows the power of incumbency, and the best example is at the top of the ballot. Gov. William Donald Schaefer seems to be overseas as much as he is on the campaign trail.When Maryland residents vote in the Sept. 11 primary election, they will face an extensive ballot but few competitive races, at least at the state and congressional levels. Things could heat up by the November general election, but the prospect now is for a low-key season.

Voter registration is lagging, and, unlike the hotly contested gun ban of two years ago, or the gubernatorial race of 1986, no single campaign has ignited voters' interest statewide.

Leading the Democratic field is Schaefer, who has banked nearly $2 million in campaign contributions and maintained a full schedule of state business that included a trip to Taiwan less than a month before the primary.

So seemingly confident is Schaefer that his reelection effort has been cloaked not in standard political rhetoric, but in a campaign of civic boosterism that presumes he will be around for four more years. The "Campaign for Maryland" is promoting civic activism on the environment, education, and substance abuse, along with promoting the reelection of Schaefer and Lt. Gov. Melvin A. Steinberg.

Challenging him in the Democratic primary is Fred Griisser, leader of the group that unsuccessfullly opposed the state's effort to prevent the sale of cheap handguns, a law backed by Schaefer.

Griisser, who has raised only a few thousand dollars, says his campaign seeks to give a choice to "normal" voters, ones he contends are tiring of Schaefer's spending and perceived arrogance.

On the Republican side, the GOP was set to challenge Schaefer by nominating William S. Shepard, a retired foreign service officer from Potomac who was expected to offer an articulate attack on Schaefer's first term. But when he named his wife as his running mate for lieutenant governor, the deal came undone; perennial Republican challenger Ross Z. Pierpont, a retired surgeon from Baltimore, entered the race just minutes before the filing deadline, saying Maryland should not be governed by a "one-family state."

Pierpont has put a kink in Shepard's fund-raising, and party regulars have not ruled him out as a possible victor in the primary.

Shepard, meanwhile, has stayed a course of bull roasts and candidate forums, trying to spread his name outside of Montgomery County, where he ran unsuccessfully for Congress in 1986.

Among the statewide issues of note this year are taxes, growth and abortion.

Tax limitation measures are on the ballot in four suburban counties -- Montgomery, Howard, Anne Arundel and Baltimore -- and concern about growth has been a launching pad for campaigns such as that of Neal Potter, the Montgomery County Council member who is challenging County Executive Sidney Kramer.

Abortion appears to be having a more selective impact, but heavy nonetheless in the districts where it is an issue. In Democratic primaries in Montgomery and Prince George's counties, abortion-rights candidates are mounting challenges against four antiabortion senators who participated in last spring's filibuster of legislation that would have guaranteed continued access to abortion in the state.

Neither Maryland U.S. senator is up for election this year, and in the contests for eight U.S. House of Representatives seats, incumbents have the advantage in seven of them.

The one exception is in the 1st Congressional District, where U.S. Rep. Roy P. Dyson is facing a spirited primary challenge following controversy two years ago over the suicide of his chief aide and the disclosure of Dyson's close ties to defense contractors.

He is challenged by state Del. Barbara O. Kreamer (D-Harford), who has campaigned against Dyson's reliance on political action committee funds and his opposition to abortion, and two other Democrats.

For the GOP, the 1st District presents the party's best chance to translate the registration gains of the past 10 years into a victory at the polls.

Eight hopefuls will square off in the primary, a situation that has left Republican officials saying they are enthusiastic about the level of interest, but worried that an interparty fight could weaken the eventual nominee.

Other state officials up for reelection are Democratic Attorney General J. Joseph Curran Jr., and longtime comptroller Louis Goldstein. Both face nominal opposition.

Howard County Executive Elizabeth Bobo (D) and the five County Council members are all running for reelection, giving citizens a chance to weigh in on whether they are satisfied with county government.

Most of the challengers in this year's races have pegged their hopes on convincing voters that the incumbents have not done enough to manage growth or county spending over the last four years. The incumbents, however, can point to actions taken on both issues.

County Republicans hope this election year will mark the start of their climb to power in county politics. Council member Charles C. Feaga (R-District 5) is the county government's only Republican officeholder, but GOP leaders say he may soon have company if their success in registering new Republican voters is any indication.

A sign, they said, of the growing Republican power in the county is the fact that Republican candidates have signed on to contest every county seat, except the one held by council member C. Vernon Gray (D-District 3). Gray is running unopposed.

There are even two Republican primary races this year.

Feaga faces a challenge from Highland resident John W. Taylor, and Gilbert E. South, of Mount Hebron, and Charles I. Ecker, of Beaverbrook, are fighting for the right to take on Bobo in the general election.

Taylor and South represent two-thirds of an informal, undeclared coalition of candidates who say too little has been done to manage the county's growth. The third member of their group is William C. Smith, who is challenging Shane Pendergrass (D-District 1) in the Democratic primary.