Outside of a U.S. President bending norms, the Fed also faces challenges in achieving its economic objectives. Inflation remains above its 2% target: Its preferred measure is at 2.4%, though core prices — considered a better gauge of where inflation is headed — rose 2.8% in November from a year ago.

Policymakers left their benchmark rate unchanged amid signs that the economy is humming along, defying the president’s tradition-bucking pressure on the central bank.