Minneapolis drew national acclaim for its farsighted 2040 plan, adopted last year. A "breakthrough," declared the New York Times, praising the city's "simple and brilliant" recognition that setting aside most of its land for single-family dwellings was harming affordability, sustainability and social equity. The new plan called for beefing up density along transit corridors and, most notably, ending single-family zoning citywide.

But now comes a way to potentially nullify that approach. A city parks commissioner has uncovered a never-used ordinance allowing homeowners to nominate "conservation districts" as a way to prevent change in neighborhoods containing "notable architectural details, building types or development patterns." The commissioner, Meg Forney, has offered her own single-family home and 25 similar homes as the first such district.

"A perfect slice of Americana" is how Forney's application describes the leafy enclave of midsize houses tucked roughly between West Calhoun Parkway and the Minikahda Club, just off Excelsior Boulevard. Neighbors there fear redevelopment because their homes are a five-minute walk to the new West Lake Street LRT station, opening in 2021. Indeed, to accommodate the new station, the 2040 Plan suggests building heights of two to 10 stories on nearby blocks.

For now, City Hall is pondering the question ahead of a Sept. 17 meeting of the Heritage Preservation Commission. The HPC will decide whether the area is worthy of study and designation. If the process moves forward, the City Council will have the final say. The issue poses a dilemma for officials: Does the area contain truly distinctive design details that warrant special protection? Or should the 2040 Plan, with its long-term density benefits, prevail?

Already sides are re-forming from last year's fierce debate on the 2040 Plan, one side claiming that without conservation districts "the architectural treasures of our city will be steadily destroyed forever," the other worrying that conservation districts could unravel the benefits of density prescribed by the plan. "Opting out sets a bad precedent," said Linnea Godestad, an advocate for the organization Neighbors for More Neighbors. "Every neighborhood thinks it's special."

So, what should city officials do? In this case, sentiment may fall on the side of preservation. Yet, the overarching benefits of urban density should not be shoved aside. Density expands badly needed housing supply in the city. That, in turn, keeps prices and rents relatively lower, lessens the need for sprawl and long commutes, reduces the carbon footprint, boosts the efficiency of infrastructure, promotes transit and other alternatives to driving, enhances economic potential in the city, and helps redress its sad history of housing discrimination.

A win-win compromise may be hiding in plain sight: Avoid a bad precedent by denying the conservation district while agreeing to rezone those few blocks for triplexes but prohibiting any larger project. The city gets some extra density, while the neighbors get a measure of protection. Not tipping its hand, the HPC is approaching the issue with caution, as it should. "This is the first application, so we want to be especially careful," said Andrea Burke, the HPC staff supervisor. "We want to set a good stage."