When a proposed piece of legislation catches flak from both the left and the right, it probably is either very good or very bad.

In this case, a bill to jail mothers and fathers for drinking or taking drugs while expecting a baby, is pretty bad.

House Bill 645 by Rep. Ken Peterson, R-Billings, is based on the idea that there should be a criminal penalty for exposing unborn children to such substances. It also would allow children to sue their parents if they were harmed.

The bill would require doctors who see evidence of alcohol or drug exposure to inform police, who would obtain a warrant to test the baby. Penalties for the parents could include a fine of up to $10,000 and up to five years in prison.

Critics at Monday's hearing on the measure included American Civil Liberties Union lawyer Debbie Smith, who said that instead of offering a workable solution, "it would contribute to Montana's already out-of-control prison population and expense." Others said it would break up families and tie the court system.

Rep. Roger Koopman, R-Bozeman, took a shot from the right, suggesting that the bill would create a "Big Brother" to interfere with families.

It is true that prenatal damage caused by parents' addictions is costly to society and can be devastating to the child, and Peterson's goal of deterrence is laudable. But the goal is better served by providing the support these parents so desperately need, not simply throwing more people into prison.