US Republicans have all but guaranteed the backing of the "gold vote" this November by raising an idea that even the most bullish mainstream bullion boosters believe is unrealistic - a return to the gold standard. Gold prices would likely surge to $10,000 an ounce, the greenback's credibility would vanish and global superpowers would risk a new trade war if Republicans were to restore the link between the US dollar and gold that was severed 40 years ago.