Annual inflation ticked up for a third straight month in December as food, energy costs rose, CPI report showed. But underlying price measure eased.

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.