President Donald Trump this week revived a long-standing threat against Jerome Powell when he accused the Federal Reserve chair of “playing politics” and moving too slowly to lower interest rates. But privately, according to people close to Trump, the president has for months been aware that trying to oust Powell could inject more volatility into jittery financial markets.

Investors are already uneasy after a period of tumult due to a blitz of tariffs announced by the administration this month. Undermining the political independence of the Fed, which is seen as critical across Wall Street, could risk a much more significant financial panic.