Each man, woman and child in Alabama would have to buy almost $150 worth of lottery tickets every year to generate the $200 million Gov. Don Siegelman promises his lottery would deliver to the state’s schools.

That’s because no lottery can pour all of its proceeds into good works. About half typically goes to pay winners. Some has to cover expenses such as administration and advertising. Just more than one-third typically goes for the public beneficiary in our case, schools.

So for Alabama to raise $200 million for schools each year, the lottery would need to sell more like $600 million in tickets. That is an unrealistic expectation. Alabama is a poor state. Its lottery would have to compete with Georgia’s, Florida’s and, perhaps by then, Tennessee’s.

It becomes even more of a stretch when you consider that the burden for generating the money won’t really be spread evenly among 4 million people. Children, presumably, would be prohibited from playing. At least some adults would never play, either. That means a much smaller number maybe half would have to spend $600 million a year for the lottery to live up to its billing.

The Alabama Policy Institute raised this point in a new study. It’s a valid issue that voters should consider before they buy into a lottery. Unfortunately, the conservative think tank tarnishes its work by arguing further that Alabama schools have plenty of money and just need better management. Alabama ranks near the bottom of the nation in spending per pupil and collects lower taxes per person than any state. While schools need to be better stewards, they need more money.

But the Policy Institute is right on one point: A lottery is no answer.

It’s an arbitrary revenue source, one that can go down over time and force states to adopt aggressive advertising or expand their gambling offerings. Moreover, a lottery preys disproportionately on the poor.

It’s a bad idea, and its time hasn’t come.