The complicated legal status of marijuana just got a little more complicated in Maine.

The weed is currently illegal under federal law, but subject to Maine sales tax in some transactions.

This is an outgrowth of the citizen-enacted law, in which an overwhelming number of voters determined that patients with certain conditions should be able to access the drug through state-regulated dispensaries.

The federal law has not changed, though, so patients who comply with the state law are still violating the federal statutes. U.S. Attorney General Eric Holder has announced that he has instructed law enforcement under his authority not to pursue cases against medical marijuana users or distributors, but attorneys general come and go, and there is no guarantee that the next one will take the same position.

That leaves states like Maine that allow and regulate medical marijuana in a strange position.

Even though you need a doctor’s note to use marijuana medicinally, the substance is not one of the prescription drugs that are exempted from sales tax. It is more like an over-the-counter medication, which would be subject to a tax.

The state will have to spend some money to monitor dispensaries and enforce the law. It is reasonable to require that some of the income generated from the sales should be collected in the form of taxes to help cover expenses.

In the short run, it makes sense for Maine to impose a tax on these legal sales (at least under our law), just as it would on other similar products. In the long run, it would make more sense for the federal law to include a medicinal exemption to remove some of the uncertainty from those who just want to follow the law — but need to know which one.