A dispute over Columbia's last large piece of undeveloped land is shaping up as a battle that may be less about competing plans and more about who's in control of Howard County.

At first glance, the issue is a proposal by the Rouse Co. to build 1.2 million square feet of commercial space, possibly including big box stores and a gas station, on a 63-acre site next to Merriweather Post Pavilion. The company also wants to eliminate parking for the amphitheater and sell it to a buyer who would downsize and enclose the popular concert venue.

Just beneath the surface, however, simmers a broader debate over who will decide the fate of Howard County's commercial heart and its largest community: politicians, planners, developers or residents?

"The community says, 'We want a say. It's in our back yards,' " said Seth Hurwitz, the concert promoter who manages Merriweather Post. "But the Rouse Co. owns the land, they want the parking lots. That's their right."

The fight is unfolding on several fronts. A community group, Save Merriweather, is pushing hard through leafleting, phone trees and testimony at hearings to get Rouse to drop plans to sell the amphitheater. The Howard County Council has been holding hearings on changes to county zoning regulations for Columbia, which have granted enormous latitude to Rouse in its development decisions.

The governing boards of Columbia's 10 villages and the umbrella Columbia Association have entered the fray, giving their views on how the final phase of downtown Columbia should unfold. Former members of the Howard County Planning Board, legislators and others also are speaking out.

Tomorrow, the future of downtown Columbia and Merriweather Post may come into clearer focus as the county's five-member Planning Board opens a hearing on the Rouse proposal. A Planning Department staff report said the development should be allowed to move forward. But dozens of county residents plan to come out to oppose it.

It is early enough in the development process that Rouse is not yet required to explain its precise plans for the parcel, known as the Crescent Property. This will be the company's second attempt to develop the land. A plan for housing was rejected this year by the County Council on the grounds that it involved too many units per acre.

Rouse Vice President Dennis W. Miller, in charge of the company's holdings in Columbia, said it plans to go forward with the commercial proposal and sees no reason the plan should be turned down. "We will be there," he said. "It's business as usual."

But other community leaders believe that the time has come to assert more local control over Rouse's aspirations.

Two County Council members, Guy Guzzone (D-Southeast County) and Ken Ulman (D-West Columbia) have proposed building a network of pedestrian bridges and using Merriweather Post as a focal point for a performing arts center and a large green space that could be Columbia's "Central Park." It is a vision they said that would fit into James Rouse's original ideas for the community.

"There will be no big box stores there," Ulman said.

Complicating matters for residents is fear of the unknown. The Rouse Co. is in the process of being sold to Chicago-based General Growth Properties, a shopping mall developer. It is not clear if it will hold on to or spin off the Rouse Co.'s community development division, which oversees Columbia.

Some speculate that Rouse is proposing big box stores -- something the community will probably complain about -- as a way to steer the debate back to housing, which could be far more lucrative.

Council member Christopher J. Merdon (R-Northeast County) said the current fight may prove to have been a sideshow.

"I believe the Rouse Company really wants housing on the property," he said. "When the council submits changes to [Columbia zoning], Rouse will take a step to submit a new plan that will incorporate residential and commercial. . . . They will take a step back and withdraw this plan."

Rouse Co. wants to have Merriweather Post Pavilion downsized and enclosed.GUY GUZZONE KEN ULMANLast month, a citizens committee toured Merriweather Post Pavilion and discussed what to do with the property. Some Columbia residents are working hard to get Rouse to drop plans to sell the amphitheater.