In fact, there’s a long history of presidents putting pressure on Fed chiefs to cut interest rates. But President Trump’s public harangues to fire Jerome Powell are unprecedented and could create more difficulties.

Trump has repeatedly urged Powell to cut the short-term interest rate that the central bank controls. The Fed typically reduces its rate during an economic downturn to encourage more borrowing and spending, and raises it to cool the economy and fight inflation when prices rise.

The president said he has “no intention” of ousting Jerome H. Powell, the Fed chair, but the administration’s willingness to challenge norms regarding the central bank’s political independence is causing concern.