City Council members can help protect constituents from a potential threat and give a group of students an unusually positive civics lesson by adopting a proposal to outlaw certain types of synthetic marijuana. Before passing it, though, they should seek some practical information on the costs of its enforcement and make clear to citizens the limits of their action.

Medical professionals, law enforcement officials and news organizations have caught up with the practice of tobacco shops and other retailers selling substances that are synthetic “cannabinoids,” designer drugs intended to produce effects similar to the active ingredient in marijuana.

Though labeled incense, buyers smoke the products – Spice and K2 are the most common brand names – but do not test positive for marijuana.

Two weeks ago, a group of students went to the council expressing concern that the product was available in some city stores. Today – in what is, for government, lightning-fast speed – the council is expected to introduce an ordinance banning the four principal synthetic cannabinoids.

As a city ordinance, the penalties cannot include imprisonment, so sponsor Mitch Harper and co-sponsor Tom Didier are seeking fines of up to $2,500 for businesses and $1,000 for individuals.

There are reasons to be concerned about the substances. As relatively new drugs, they have been the subject of little study. No one really knows the long-term effects. Medical professionals report anecdotal evidence that, compared to marijuana, the new synthetic drug is more addictive, its effects more intense, withdrawal more difficult. Its effects on the lungs are unknown, but they probably aren’t positive.

Germany outlawed the drug last year, and so far six states – including Kentucky – have adopted bans. Illinois and Michigan are considering them.

The City Council can unquestionably move faster than the statewide General Assembly, which doesn’t meet until January. But first, council members should ask:

•Will city police actively enforce the ban? Unless police target stores that sell it, the ban will have little real effect.

•Is that a good use of police resources?

•Will the city attorney’s office be able to prosecute the cases with existing staff, or will it have to hire consulting attorneys for the first cases? Because the ban is a relatively new area of the law – and a city ordinance banning specific drugs even more unusual – will the city need specialized expertise?

If the law takes effect in September, stores that sell the substance could simply stop. They might wait to see whether the police enforce it.

They might challenge the ordinance, a process that could last well into 2011 – perhaps past the date when the legislature enacts a statewide ban.

Even if a nationwide ban is enacted, however, new forms of synthetic cannabinoids could be developed, starting the process over.

None of this means the council should necessarily reject the proposal.

If the City Council inspires other cities to adopt similar ordinances, it could dramatically cut down availability and spur the state General Assembly to move faster.

But council members should understand the realistic effects of such an ordinance before approving it.