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- BRICS countries could swing an "economic wrecking ball" at the dollar, a former White House economist says.
- The bloc has growing power and influence in global trade as it adds new members.
- The US dollar could soon be in the same position as the British pound in the 1800s, he said.
The dollar could face a growing challenge from BRICS countries, thanks to the bloc's growing size and influence over global trade, according to former White House economist Joe Sullivan.