Bernstein suggests commodities are a viable way to play a potential weakening of the US Dollar. If the Fed cuts rates while the economy remains hot (high nominal GDP), the dollar is likely to depreciate. Commodities are "hard assets" that historically appreciate when the currency they are priced in (the dollar) loses value. Historical correlation between falling dollar and rising hard asset prices. If the Fed becomes more hawkish (e.g., under a nominee like Warsh), the dollar could strengthen, hurting commodity prices.