The most alarming thing about Mr. Obama’s proposal is that the $250,000 threshold, above which the payroll tax would be applied, refers to household income, not individual income. So it’s quite deceptive when he claims that the $250,000 threshold will “ensure that lifting the payroll tax cap does not ensnare any middle class Americans.”

Suppose your household consists of you and your spouse, each earning wages of $150,000 per year. Currently, you are each subject to the payroll tax up to $102,000 of wages, so together you are taxed on $204,000. Under the Obama plan, you’d be taxed again on another $50,000 of wages.