WASHINGTON—The U.S. Federal Reserve needs to begin raising interest rates but it is too soon to say how far or fast that process will need to go to bring inflation under control, Richmond Federal Reserve president Thomas Barkin said Thursday. He said it remained uncertain, given the ongoing pandemic and the tangled state of global supply chains, whether U.S. inflation would dip on its own back towards the Fed’s 2 percent target, or be driven persistently higher by rising wages, higher input costs, and businesses developing more aggressive pricing strategies. With the Feds’ target policy rate still near zero, he said, the immediate challenge is “to get ourselves in a better position to do what we might need to do should the least optimistic scenario come true, while not constraining the economy” in the meantime, Barkin said in a Reuters interview. “It is a straightforward call to say we ought …