As a planning consultant with a 40-year career dealing with planning and zoning issues in the region, I bring some perspective to the commentary on zoning in Uptown ("Know your zoning: Beware the high-density disaster," Jan 2).

The author writes: "A city's zoning regulations form a pact with its neighborhoods. That pact has an ethical component. It is a kind of promise to maintain the livability of that neighborhood for those who invest their savings in homes there." And also: "Zoning includes an implicit contract ... to maintain livability and safety around the parks and lakes."

First, zoning is simply a legal tool to regulate land use. I would not characterize it as a "pact" or a "contract." It is a local law that can be modified as the City Council wishes. Zoning allows a city to regulate characteristics of development on private land, including density, setbacks, height and more. The city gets this authority from state statute, and zoning codes also need to follow principles in the U.S. Constitution — due process, equal protection and takings.

But nothing in this scheme suggests a pact with a neighborhood or that maintaining current conditions is the focus.

Zoning is a tool to implement a city's comprehensive plan. The plan might be considered a pact, but it too can be changed — and should be changed as conditions change. There can be honest discussion about what constitutes "livability." In a place such as Uptown, there are many opinions on what this means and what the plan and zoning should be. There is no one right answer. Sometimes preserving a certain character is the right thing; sometimes changing things drastically is the right thing. Ultimately, it is up to the City Council to make that call, ideally after robust discussion and engagement with the affected community.

As I frequently tell my students in zoning seminars, zoning codes did not come down from the Mount with Moses; they are products of human effort and should be changed as necessary to reflect a community's wishes.

I commend residents for speaking out about the details and impacts of proposed development — that is how the system should work. But zoning itself does not have a responsibility to preserve the status quo.

Philip Carlson, of St. Paul, is a city planner.