The US once nearly picked its president based on a fight over silver coins
Bimetallism means backing a currency with two metals, usually gold and silver, at a fixed exchange ratio set by law rather than the market. When one metal's market price drifted from that legal ratio, people hoarded the undervalued one and spent the overvalued one, destabilizing the system. The fight over reintroducing silver dominated 1896 US politics, climaxing in William Jennings Bryan's 'Cross of Gold' speech.