In a tweet, Trump blasted China and Europe for playing a 'big currency manipulation game' and recommended that the US "MATCH" or risk being "the dummies who sit back and politely watch as other countries continue to play their games."

Notably, the tweet calling for even more easing followed Trump's latest tweet celebrating new market highs.

Trump's warning also comes less than two weeks after Bank of America warned that direct intervention to weaken the dollar would be possible by a few avenues, some directly involving Trump (jawboning), some involving the Treasury and the Fed (direct intervention by the NY Fed's New York markets desk).

Whatever the administration decides, it's becoming increasingly clear that the dollar is unsustainably overvalued compared with its long-term real effective exchange rate value. BofA's analyst calculated that the dollar is 13% above its long-term average.

According to tradition, the dollar and its value have long been the exclusive purview of the Treasury Department. But Trump has never been one to unquestioningly adhere to precedent. And back in May, the Treasury Department declined to name any country to its list of currency manipulators, though it added some to a 'watch list'.