Just as certainly as the public generally hated the recent Supreme Court ruling on the use of eminent domain, some states will overreact and set limitations on government so strict that the public good will be run over in the pursuit of protecting private property. Maine should make sure it is not one of those states.

The case before the court was Kelo vs. the City of New London, in which homeowners in an economically distressed section of New London, Conn., fought unsuccessfully to prevent the city from taking their homes, for just compensation, to encourage private economic growth the city hoped would provide a public benefit. The majority of the court said the city could take these homes because it had a carefully considered plan in which the public benefit was not incidental to the development and the expected gain was broad and substantial.

The ruling demonstrated a serious underestimation of the prevalence of the sort of city revitalization proposed in New London and gave too little weight to a public’s interest in being secure in their property. A half dozen state legislatures immediately devised statutes to restrict the use of eminent domain when transferring property to a private owner. Maine is now considering adding to its own prohibitions. It should do so carefully – rigid formulas are as likely to cause nearly as much grief as the loose ruling by the court.

For a guide, Maine’s Legislature would do well to consider the dissenting opinion in Kelo, written by Justice Sandra Day O’Connor, in which she separates the legitimate and doubtful use of eminent domain in the area under debate. Justice O’Connor first notes two areas in which taking property, for proper compensation, is widely accepted: when it is transferred from a private entity to public ownership for a road, a military base or a hospital, for instance. Or when it is transferred to a private party that provides public accommodation, such as a railroad or an electric utility.

But a third class of takings is more difficult – when private land is transferred to a private party because a more productive use has been identified. The courts have said this was acceptable where urban blight threatened public health and safety and, in a case 20 years ago in Hawaii, when oligopoly ownership patterns, according to the legislature there, was “inflating land prices and injuring the public tranquility and welfare.” In those cases, wrote Justice O’Connor sensibly, “a public purpose was realized when the harmful use was eliminated. Because each taking directly achieved a public benefit, it did not matter that the property was turned over to private use.”

Here is a guideline for lawmakers. Is the taking itself a public benefit or is it supposed to generate a public benefit? The difference between the two is the difference between the cases Justice O’Connor cites and the Kelo decision. While not without its own gray areas, this distinction reduces the problem of nearly any piece of private property being identified as having the ability to generate some higher incidental use to the public and therefore at risk of being taken.

Maine has laws already that shield property owners in eminent domain cases; making Justice O’Connor’s distinction clear could provide further protection.