Sen. Barack Obama has a bad idea for "extending the life of Social Security." He has proposed applying the Social Security tax to incomes above $250,000, in addition to the current tax on incomes up to $102,000. It's unfair, he explained, for middle-class earners to pay Social Security tax on "every dime they make" while the very rich pay on "only a very small percentage of their income."

Reporters cited the Obama statement without asking for the logic behind having someone making $100,000 pay on every dime and someone making...