The income tax only taxed the Rockefellers, the Morgans and the Vanderbilts. It was aimed at the top 4 percent, and the top rate then in 1913, was 7 percent. Woodrow Wilson had a big ceremony and said, "I'm delighted to be president at the creation of this popular new tax."

If your employer pays your health insurance, that's not counted as income to you. And any economist would say that's your income, because they'd pay a higher wage if they didn't take it. That's a huge loss to the Treasury.

Starting in the '80s or so, after the United States sharply cut its rates, other countries decided they better do it too, and here's how you do it: you just wipe out the exemptions, the deductions, the credits, the depreciation allowances. And people complain, "Oh my God, it's terrible," but you give them much lower rates and you give them an easier form to file, and people accept that tradeoff.

Mortgage is one of the most popular deductions. It costs the Treasury about $103 billion a year. Now that's money we could use to treat wounded veterans or reduce the deficit or fill the border. Instead, we give it a subsidy to homeowners, and it goes mainly to the richest homeowners in America, because only one third of Americans itemize their deductions. It doesn't work. Many countries have gotten rid of the mortgage interest deduction. Almost all of them have higher homeownership rates than we do.

The Value-Added Tax, a sales tax that applies at every level of business transactions, is an easy tax for governments to collect, and a hard tax to evade.

In the United States, unlike any other advanced democracy, money really talks. Our Supreme Court has said that spending money on politicians is a form of free speech. No other court has said that.

When it comes to taxation, Americans are still banging out letters on a typewriter and dropping them in the mail box while everybody else has moved on to texting and Instagram.