How much should a unit of housing cost? It all depends on what you are buying. This is the crux of the argument between State Treasurer Bruce Poliquin and the Maine State Housing Authority, which Poliquin says has wastefully spent taxpayer money on overpriced “affordable” housing.

But the treasurer’s case doesn’t stand up to scrutiny, and, typically for him, turns a legitimate policy question into a partisan political slugfest.

Poliquin’s poster child is Elm Terrace, a rehabilitation of a historic building in downtown Portland that at one point was projected to cost $314,000 a unit. Poliquin asks why a state agency should be supporting such a project when the median single-family home in Maine sells for about half the price.

There is a kernel of truth in Poliquin’s critique: Elm Terrace does have a high per-unit cost, although not as high as the preliminary figure he cites. The cost reflects a multi-unit apartment building with sprinklers and elevators that is built to comply with handicapped accessibility and other codes that don’t apply to existing single-family homes. It is also in a historic building, and renovation is more expensive than new construction. But Poliquin glosses over other facts to the point of distortion.

It may come as a surprise to some that not a single dollar of taxpayer money from the state’s General Fund will be spent on Elm Terrace. Instead, federal tax credits were awarded to a private developer, who used them to leverage private investment in a project that would not otherwise be built.

The tax credits were awarded by MSHA in a competitive process, in which proposals were scored on a variety of criteria. It benefited from state anti-sprawl law that favors the reuse of downtown structures.

This is the real policy question in this debate, but the agency that oversees these transactions is not the place to argue it. If Poliquin believes that it makes more sense to build low-cost housing in rural areas — far from employment and service centers, putting pressure on rural roads and schools and increasing energy bills — the place to make that case is before the Legislature. The housing authority should not ignore the law just because the treasurer disagrees with it.

There is more than one way to be careful with the taxpayers’ money, but political cheap shots is not how to find the best way.