Stephen Moore has drawn swift and unusually pointed criticism after President Donald Trump picked him to be a governor of the U.S. Federal Reserve, with at least one prominent Republican economist calling on the Senate to block the appointment.

"He does not have the intellectual gravitas for this important job," wrote Greg Mankiw, a Harvard professor who was chairman of the White House Council of Economic Advisers under President George W. Bush, in a blog post on Friday. "It is time for senators to do their job. Mr. Moore should not be confirmed."

Moore's selection is subject to Senate approval. He's Trump's sixth nomination to the nation's monetary authority, which has a seven-seat board of governors that typically is filled with trained economists, former financial-industry executives and bank regulators. There are currently two vacant seats.