After the deal with Penske fell through this week, GM has decided to retire the Saturn brand for good.Car dealership operator Penske Automotive Group announced on Wednesday that it has cancelled plans to acquire General Motors' Saturn unit. As a result, GM said it will wind down the brand and dealer network, potentially putting 13,000 Saturn dealership jobs at risk.The announcement comes nearly four months after Penske agreed to buy the rights to the 19-year old brand from GM when the automaker was in bankruptcy. As part of the deal, GM would have continued making Saturn's three best-selling models -- the Aura sedan, as well as the Vue and Outlook cross-over SUVs -- for the rest of this year and next. Penske, which is an auto distributor and not a manufacturer, would have sold the cars on behalf of GM. Penske said it would find another third-party manufacturer to make new Saturns in 2011.But negotiations with another, unnamed manufacturer fell through after an agreement was rejected by that manufacturer's board, according to Penske. According to a report in the Wall Street Journal, the manufacturer in question is Renault."Without that agreement, the company has determined that the risks and uncertainties related to the availability of future products prohibit the company from moving forward with this transaction," the company said in a statement.So another 13,000 jobs about to get canned, more dealerships closed, etc. Our car nation is taking it right in the economic engine here, folks. Good manufacturing jobs created the middle class in America. Now they are the herald of the death of the middle class.