I dont know either way if gold is manipulated or not specifically by the US Gov., I find technical analysis and other indicators useful on all timeframes for investing in gold and I can't say I have seen "unusual" action on a bigger time frames. Gold and Silver have performed as I would expect based on the action in DX and credit conditions up until now.

Otherwise the global economy is too interconnected for the US to take extreme measures by itself, last year has confirmed in my mind that all economic problems are global in nature so I cant see the EU or Asian govs confiscating gold