I am sure the proposition that “everyone should pay income taxes” seems obvious to you and me. And yet, the reality is quite different. Over at the Wall Street Journal, Ari Fleischer, Pres. George W. Bush’s former press secretary, has some interesting numbers about how many taxpayers pay the income tax, and how much each group contributes.

At the top:

A very small number of taxpayers — the 10% of the country that makes more than $92,400 a year — pay 72.4% of the nation’s income taxes. They’re the tip of the triangle that’s supporting virtually everyone and everything. Their burden keeps getting heavier.

At the bottom:

According to the CBO, those who made less than $44,300 in 2001 — 60% of the country — paid a paltry 3.3% of all income taxes. By 2005, almost all of them were excused from paying any income tax. They paid less than 1% of the income tax burden. Their share shrank even when taking into account the payroll tax. In 2001, the bottom 60% paid 16.3% of all taxes; by 2005 their share was down to 14.3%. All the while, this large group of voters made 25.8% of the nation’s income.

While very politically appealing, it has some serious economic implications:

Picture an upside-down pyramid with its narrow tip at the bottom and its base on top. The only way the pyramid can stand is by spinning fast enough or by having a wide enough tip so it won’t fall down. The federal version of this spinning top is the tax code; the government collects its money almost entirely from the people at the narrow tip and then gives it to the people at the wider side. So long as the pyramid spins, the system can work. If it slows down enough, it falls.

The open question is: When will it stop spinning? Read the whole thing here.