If the government can manipulate markets up...

they can certainly manipulate markets down with intervention in the derivatives markets, whether the underlying asset classes are equities or commodities (precious metals and energy).

http://ftalphaville.ft.com/blog/2010/01/06/120796/trimtabs-on-that-%E2%80%98us-government-rigged-stock-market/

Rigged markets force investors to become speculators--trying to front run big players, especially if the 800-pound elephant is Uncle Sam himself. Deciphering financial statements is no longer enough. There is no such thing as a free market anymore, and participants should understand that before venturing down into the deep end of the pool.