National Trust petitions Supreme Court in Carnival lawsuit, P&C, April 13, 2012.

The National Trust for Historic Preservation, considered the leading advocacy organization for protecting America’s historic places, is wading deeper into the debate over cruise ships in Charleston. The findings of this widely respected group warrant serious consideration.

Last year, the NTHP put Charleston on “watch status” for its Most Endangered Places list. Then it helped sponsor, along with the Historic Charleston Foundation, a tourism impact study to assess economic, social and cultural impacts that increased levels of cruise traffic will have on historic Charleston.

Most recently, based partly on data from that study, the NTHP has filed an amicus brief with the S.C. Supreme Court supporting a lawsuit filed by the Preservation Society of Charleston, the Historic Ansonborough Neighborhood Association, Charles Towne Neighborhood Association and the Coastal Conservation League. They are seeking legal limits to restrain the impact and growth of Carnival Cruise Lines in Charleston.

Carnival is the State Ports Authority’s largest cruise ship client, and with the approval of the city, the SPA is steaming ahead. On Wednesday, it passed a major hurdle as the city’s Board of Architectural Review approved the design of a new passenger terminal.

Next, the Office of Ocean and Coastal Resource Management will decide whether to allow the SPA to set five pilings as supports for the terminal’s elevator and escalators. A hearing is scheduled for next Wednesday.

Some who want the industry to be subject to legal controls plan to object to the request, citing environmental concerns.

The NTHP concurs with the plaintiffs in the lawsuit that peninsula Charleston is being adversely affected by crowding, traffic and air emissions from cruise ships, and that Carnival’s massive ships loom over the skyline and block the city’s famous harbor views.

The city of Charleston, which attached itself as a co-defendant in the suit, contends that the plaintiffs do not have standing to join the lawsuit. NTHP lawyers cite numerous court cases to show that they do. The plaintiffs or people they represent have property in historic areas that are restricted by ordinances and are directly compromised by cruise ships. The lawyers also say that those plaintiffs have expenses related to cruise ships.

A hearing date hasn’t been announced.

The National Trust, founded in 1949, has more than 300,000 members and works with thousands of preservation groups in all 50 states. Over the years, it has recognized Charleston for its notable success in preservation and tourism management. In 2009, it presented its Preservation Honor Award to the city, the Historic Charleston Foundation and Page & Turnbull, Inc., for the Charleston Preservation Plan.

The city, which has delighted in accolades from the foremost preservation group, has brushed off the NTHP’s current concerns.

The NTHP, in its brief, notes that Charleston has, by law or private regulation, protected its landscape, architecture, building materials, church steeples, historic skylines and water vistas: “Unregulated cruise tourism, however, has started to jeopardize the maintenance of this fragile environment that generations of Charlestonians have worked hard to protect. Carnival has refused to place reasonable limits on the size and frequency of its ships. In fact, Carnival has refused to be regulated at all. … And it has done so with the approval of the State and the City.”

Some are framing this debate as whether or not to eliminate cruises to Charleston.

But it actually is about reasonable limits that are legally binding — limits that would help keep Charleston the place that the National Trust for Historic Preservation has heralded in the past and that residents love.