FALSE advertising is part of the problem, and it’s right there in the name: alternative minimum tax.

“Minimum,” when the tax was conceived, meant that even the wealthiest Americans, with their buffet of deductions, loopholes and shelters, would still pay some income tax.

“Alternative,” added to the name of the tax 21 years ago, suggests a choice, but it’s not much of one for one in four taxpayers this year who must pay using this calculation unless Congress comes up with a different “alternative” when it takes up the matter this week.

What happened between 1969, when the minimum tax was born, and today, when it has few champions — and many people scratching their heads? And how could it be that a tax aimed squarely at rich investors who paid no income tax now hits middle-class families?

The ’69 version of the tax was more or less what it set out to be, right or wrong. And that was a remedy to the disclosure by the Johnson administration that 155 rich families some of whom made millions in 1966 had not paid any taxes — taxes that for other Americans were rising to pay for the Vietnam War. If deductions like the ones for owning oil wells and leasing rail cars had whittled some tax bills down to nothing, these rich earners would be required to pay something.