Maryland has started another tax amnesty program, this one from now until Oct. 30. Tax scofflaws -- who owe Maryland as much as $500 million, according to the comptroller -- can pay their arrears without penalty.

This is Maryland's third tax amnesty since the Federation of Tax Administrators began keeping track in 1982. We had one in 1987 and another in 2001. At some point these things are going to stop paying off. Maybe they already are. The 1987 holiday raised $35 million for Maryland. The 2001 one netted $39 million. This time officials are talking about $5 million or $10 million.

It's a great deal for the tardy taxpayer. Not only are penalties waived. This time so is half the interest, which in Maryland is practically at Tony Soprano levels -- 13 percent!

Taxpayers are rational, and they can see that amnesties are becoming more than the one-time deals that they're advertised as. In most states amnesties crop up when recessions hit and comptrollers are hard up for dough. If you owe back taxes and you see the fiscal situation deteriorating, governors and legislatures are sending you a message: Just wait, folks, because we're so desperate that soon we'll change the rules in your favor.

States offering tax amnesty this year include Alabama, Arizona, Connecticut, Massachusetts, New Jersey, and Virginia, according to The Tax Adviser. At least some policymakers are starting to worry that enough is enough. A New Mexico fiscal analyst quoted by The Tax Adverser recently warned: "frequent amnesty periods may indirectly communicate a message to taxpayers that they do not need to comply with the Tax Administration Act because, potentially, another amnesty period may be approved."

These days "potentially" is becoming "inevitably."