No matter how many times it’s been defeated at the ballot box — NOT winnning even in the low income districts — what’s wrong with Dorchester Robert Frank might ask — the impulse for a progressive income tax is back with the new Standard and Poor’s study. (That’s the same S&P that failed to foresee the Wall Street implosion back in 2007.) By the way bond ratings agencies hate spending cuts and love tax revenue. Each Democrat running for office ought to go on the record on where they stand on the progressive income tax. This is a winning issue for the GOP even in the land of Occupy Boston and class warfare.