They say never to go grocery shopping on an empty stomach. In 2009, at the nadir of the crisis for automaker Chrysler, a desperate Treasury Department team led by Steve Rattner put together a deal for Chrysler that left Italian automaker Fiat with a 20 percent stake, with the option to buy another 50 percent. While the U.S. and Canada have sold their combined stakes to Fiat, the union’s health-care trust owns the remaining 68 percent. Surprise, surprise—the union and Fiat are duking it out in court over rival valuations of the company. The difference: $6 billion.