China has crafted markets, mechanisms and incentives as the world’s largest buyer of commodities in a bid to free itself from its dependence on the US dollar, but the biggest threat to Washington’s global dollar dominance may well be Washington itself, witnesses said in testimony on Thursday before a key advisory committee to the US Congress. Economic sanctions and access to US-led global banking systems are a powerful US tool that can be used to great effect, said experts before the US-China...