Powell has never responded directly to Trump's provocations, and I, personally, expect this issue to play a predominant role at his latest meeting in Jackson Hole, perhaps even more so than the interest rate discussion. The independence of central banks is much more important than a 25 basis point change in the coming month.

Financial markets are taking in a collective breath ahead of Jerome Powell's eighth and final keynote Jackson Hole speech as Federal Reserve Chair. If the moves following his last seven are any guide,