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.