if it were just the government against investors, the manipulation could go on for a very long time. but foreign governments know what is going on, too. the russians, chinese, and arabs have their own interest to protect. the countries that hold large amounts of us treasuries are not happy with depreciating currency, and will diversify into gold sooner or later. everyone knows the us dollar is overvalued, and the supply of gold is miniscule compared to the number of dollars floating around the world.

i don't know what event will cause the first country to start buying gold openly (some have undoubtedly already done so covertly) but all it takes is for one country to break ranks and start buying. it could be the russians being angry over low oil prices, or some geopolitical event in the middle east or india/pakistan. one day the markets will be trading as usual, and the next day gold could be revalued substantially higher. it happened in the 1970's: the us dollar was redeemable in gold until france actually demanded gold instead of dollars; then the gold window closed forever.