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.

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.

France, they're the world champion at soaking the rich on taxes. And at one point, they had what they called a hyper tax, 75 percent, and Gérard Depardieu and many others left the country.

It was an easy thing to tax for a young country. And then gradually we moved to property taxes, manufacturing taxes, and the income tax was the answer to a populist demand: Let's go after the rich guys. We got into World War I, and they raised the rates and started taxing the rich. Then we got into World War II, and that's when they taxed everybody, because they just needed more revenue.

The U.S. has the most complicated and difficult tax system in the world; we've made it hard to file and pay taxes.

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.

If you get rid of all these giveaways and loopholes and deductions and credits, then you can sharply lower the rates.