Rhode Island's highest court heard arguments Tuesday in a fight that has pitted dozens of members of the Vanderbilt family against a nonprofit that owns several Gilded Age mansions in Newport.

The nonprofit Preservation Society of Newport County wants to build a visitors center on the grounds of The Breakers, a spectacular mansion built by Cornelius Vanderbilt II.

Dozens of preservationists, as well as designer Gloria Vanderbilt and nearly four dozen Vanderbilt relatives, have said the center as planned would "permanently mar" the national historic landmark.

Two members of the Vanderbilt family attended Tuesday's arguments before the Rhode Island Supreme Court over two separate lawsuits. But the arguments involved zoning and licensing issues raised by neighbors and the city, not the family's objections and the question of whether the center would hurt the historical integrity of the site.

The Preservation Society wants to build the center to give visitors a place to buy snacks and sandwiches, use accessible restrooms and buy tickets indoors. They have argued The Breakers is a museum, and museums should be allowed to serve food.

Daniel Prentiss, a lawyer for the neighbors' group, told the Supreme Court that The Breakers is in a residential zone in "one of the most famous neighborhoods in the country." The neighborhood is packed with mansions and bordered on one side by the Atlantic Ocean and Cliff Walk.

Allowing food to be served at The Breakers, Prentiss said, could open the door to museums serving food elsewhere in the neighborhood and city.

But Preservation Society lawyer William Landry said most museums around the world allow patrons to have a glass of wine and a meal, and the Preservation Society would have to meet certain requirements for food service.

"This is no license to have McDonald's in every museum in Newport," Landry told the justices, adding that The Breakers hosts 400,000 people from all over the world every year.