Goldman Sachs lawsuit

"Although Goldman Sachs held various positions in residential mortgage-related products in 2007, our short positions were not a 'bet against our clients.' " Instead, the trades were used to hedge other trading positions, the bank said."

Could someone please explain to me how hedging your bet and betting against are at all different. I have to confess to being a trifle confused...

http://www.nytimes.com/2010/04/17/business/17goldman.html?src=tptw