From the article:
Perhaps no one would be happier about that than President Donald Trump. Here’s why: As Yale economist Robert Tiffin explained in the 1950s, if a country’s currency is the international reserve currency, then it has no choice but to run a current account deficit.
If a replacement is found, as the dollar replaced the British pound in the 1920s, it may be more likely to have trade surpluses – which is what Trump has said he wants.
Was it really the 1920’s or was it post WWII? I don’t actually remember which it was. (regarding info in the article)