ANNAPOLIS -- In their living room, with its huge cathedral-style window overlooking the Severn River and a private pier, David and Charlene Gassaway have put up a map of a less-secluded slice of Anne Arundel County.

The communities on that map -- Maryland City, Odenton, Gambrills -- are places the Gassaways used to know little about. But that was before they became lieutenants in an organization fighting for lower property taxes and characterized by military-style precision.

The Gassaways and other Anne Arundel Taxpayers for Responsive Government are fighting to get an initiative on the November ballot to strictly limit the amount of revenue the county can collect in property taxes each year.

David and Charlene Gassaway said they joined the tax protest after calculating what their financial situation will be in 10 years, when they plan to retire. They pay about $300 a month in property taxes now and estimate they will have to pay $2,000 a month within a decade if assessments continue to rise steeply. "We have worked hard for this house. And now we can't enjoy it," Charlene Gassaway said.

The tax group contends the county budget could sustain a multimillion-dollar cut without jeopardizing essential services, such as education and public safety. That contention is disputed by public officials, who note that 71 percent of the county's budget is devoted to those two areas.

According to County Executive James Lighthizer (D), "There may not be any diminishment in services they think are important, but there darn will be for education. You can't institute those kind of cuts and say . . . things like public safety {won't} be affected.

"I'm saying every single government service will be negatively affected."

These days the Gassaways can talk a blue streak about who is registered to vote in the Fourth Councilmanic District, the names of the civic association leaders and which volunteer fire department has the best facilities for large meetings.

Most importantly for their tax fight, they know which district residents are fed up with rising property taxes and have been willing to sign their initiative petition.

The drive to collect the 10,000 signatures needed to get the tax measure on Anne Arundel's ballot is similar to taxpayer revolts in Fairfax and Montgomery counties. It would be difficult, however, to find a more organized group of tax protesters anywhere.

Many county officials and community groups say there is no longer any point in struggling to keep the property tax initiative off the ballot. That skirmish is lost, they think. Instead, they are putting their energy into an effort to defeat the initiative at the voting booth.

Before taking the petition drive to the streets, the Anne Arundel tax group's leaders organized a legion of district chiefs and precinct captains to target the most promising areas.

Sensitive to the trouble their Fairfax County counterparts had in getting petitions verified, they have coached volunteers on the ins and outs of "good signatures" -- those that come from the hand of a registered voter and preferably gathered by canvassing neighborhoods -- and "bad signatures" -- those collected at booths set up at shopping centers. Canvassers have been equipped with voter-registration lists, so they can be selective about their stops, and forms, so they can register voters on the spot.

"Each person who sends back a petition is going to get a thank-you note," Charlene Gassaway said.

In many ways, the Anne Arundel tax group's focus on organization is not surprising. The group's president, Robert C. Schaeffer, is a retired Navy captain. The petition committee chairman, Joseph Smith, is the former commander of the Naval Observatory in Washington. Engineers and retired military personnel form a strong core of the canvassers.

The tax protesters are seeking to amend the county's charter to require the County Council to set a property tax rate next spring that would bring in the same amount of revenue as in fiscal 1989, or $180 million. The county's fiscal 1991 budget, which will take effect in July, anticipates property tax revenue of $210 million.

Budget officials predict that at the current tax rate of $2.51 per $100 of assessed value, the county would have $225 million in property tax revenue on hand to spend for fiscal 1992, when the tax-limit plan would take effect. Thus, the proposed tax limit would mean a cut of $45 million the first year.

The Anne Arundel tax group says that, if their plan takes effect, homeowners would see a 20 percent reduction in their property tax bills during the first year.

In subsequent years, the amendment would allow property tax revenue to increase 4.5 percent or at the rate of inflation -- whichever is lower.

All of the declared candidates for county executive oppose the tax group's proposal, calling it too drastic. Yet Schaeffer expects the petition effort to top the 10,000 mark within days. The group plans to continue gathering signatures until the Aug. 13 deadline to ensure that they have plenty even after some are disqualified.

"I'd say that 90 percent of the people we ask are signing," Schaeffer said. "What we have to do now is figure out how to transform our signature-gathering organization into a campaign organization."

That "campaign" will pit the tax group against, among others, the local teachers' union, which sent out a scathing letter denouncing the property tax proposal as the work of "misguided and selfish individuals . . . who believe they stand to gain during a reign of anarchy."

The tax measure is also drawing opposition from unexpected quarters. Jeanette Whessel, executive director of the county Chamber of Commerce, expects her organization to lobby against it, under the assumption that businesses would be asked to make up a revenue shortfall. And the chairman of the Advisory Council on Aging, John Mogey, said his committee plans to oppose the tax plan in a newsletter to 5,000 senior citizens, a group the tax protesters were counting on having in their camp.

County Executive Lighthizer and County Council member Carole Baker (D-Severna Park), both of whom are leaving office, said they plan to wage a major counteroffensive as well by rallying parents, recreation enthusiasts and supporters of the arts.

Both officials said they believe the tax group's rhetoric has been more passionate than accurate. "I think the true believers are essentially a small group of retired people with government pensions: People who have gotten theirs and now don't want to pay for the next generation to get theirs," Lighthizer said.