Dhaka, April 23 -- A selloff in US stocks, long-term government bonds and the dollar clearly traces back to policy choices by President Donald Trump's administration. Recent moves spawn a trio of worries: first, that a trade war will hit business and destabilise the United States' role in the world; second, that a $4.5 trillion tax cut plan could explode an already-historic fiscal deficit; and, finally, that pressure on Federal Reserve Chairman Jerome Powell could warp monetary policy. Trump has not yet forced an irrevocable break, but cracks are spreading at an alarming pace.

Investors are piling into short-term US debt even as longer-term Treasuries sell off, a potential sign of hesitancy to bear the risk of erratic policy shifts. Yiel...