Kerry said Friday night that he would not increase the tax burden of people making less than $200,000 in his first term. That takes off the table his major idea for solving Social Security’s solvency problem: lifting the cap on payroll taxes. Bring on those benefit cuts! (Kerry could, of course, raise income taxes and finance the program’s long-term liabilities out of general revenues. But he can’t raise income taxes on people making below $200,000 without breaking his pledge; and if all he’s doing above that figure is to undo the Bush tax cuts, he’s not going to raise enough revenue to fund his other promises, let alone Social Security.)