Washington is renowned for having a short memory, so as Congress considers what to do with Fannie Mae and Freddie Mac, we taxpayers must remind it of the harmful role the duo played in the subprime mortgage meltdown. Congress authorized these government-sponsored entities, or GSEs, to purchase mortgages from banks and other originators and package them into securities with guaranteed payments for investors. That was supposed to expand the amount of investment flowing into mortgage finance, making it easier and cheaper for middle-income families to buy homes. But as for-profit entities, the GSEs discovered they could make big bucks operating essentially like giant hedge funds, issuing cheap debt with implicit government backing and investing the proceeds in high-yield, high-risk mortgage securitizations issued by Wall Street. They made zillions for their shareholders and management until, of course, the housing market turned and mortgage defaults skyrocketed, leaving their highly leveraged operations insolvent and wards of the state.