Twice a week for the past four years, thousands of Carnival Fantasy passengers have embarked and debarked here.

But as the cruise business churns along, plans to enhance its operations with a new passenger terminal have gone nowhere.

Indeed, just this month, the Advisory Council on Historic Preservation (ACHP) sent a letter to the commander of the local U.S. Army Corps of Engineers unit to ascertain if any progress at all was being made.

It has been more than six months since U.S. District Judge Richard Gergel ruled that the Corps had failed to do due diligence in assessing the SPA's permit for a new passenger terminal. He threw it out.

Meanwhile, neighbors, preservationists, environmentalists and health professionals continue to contend with cruise ship emissions, crowding and fears that their property values are dropping.

While the SPA has not reapplied for the permit to add pilings, a spokeswoman says plans to build the new terminal have not been abandoned.

The Corps has to wait for that application to be submitted before it can try to meet the demands of the court.

Those demands include showing that the passenger terminal would not threaten the timeless ambiance of the historic district.

That is vitally important to ACHP, which "promotes the preservation, enhancement, and sustainable use of the nation's diverse historic resources, and advises the president and Congress on national historic preservation policy."

ACHP is not new to Charleston. In the 1970s, the council played a pivotal role in relocating the terminus of the proposed James Island connector from Beaufain Street to Calhoun to minimize threats to the Historic District. ACHP also encouraged the city of Charleston to expand its Old and Historic District.

In her letter to the Corps commander, ACHP assistant director Charlene Dwin Vaughn said that the council has heard concerns that "the new cruise ship passenger terminal would result in long term and cumulative adverse effects to the Charleston Historic District (HD), a property designated a National Historic Landmark and listed on the National Register of Historic Places." She notes that concerns aren't just from residents. "The National Trust for Historic Preservation placed Charleston's HD on a special watch status in its 2012 list of 11 Most Endangered Historic Places, and the World Monuments Fund added the HD to its Watch List in 2012." Both designations were in light of the cruise industry.

Clearly the Corps will have to determine the likely impact on the Historic District of a massive new passenger terminal and minimize any harm. The SPA's first application didn't receive such scrutiny.

The careful and thorough analysis is critical, and arriving at a plan that spares the Historic District harm, eliminates emissions that jeopardize people's health and considers the quality of life in the Historic District would be a win for the port as well as Charleston, which serves as a magnet for numerous cruise ship passengers.

Let's base decisions about the cruise industry on firm data, and not let the debate get personal. It's worth the extra time and effort.