Gary Cohn does not have what it takes to be the head of the Federal Reserve, former Fed Governor Mark Olson said Friday.

“He might be a genius and he might be one of the top financial market analysts in the world but he’s a beginner at monetary policy,” Olson said in an interview on CNBC Friday. “You cannot come in as the chair of the Fed as a beginner.”

Olson’s criticism of Cohn, currently the chief economic adviser in the White House, was the harshest yet coming from a former Fed policy maker. Olson was appointed to the Fed Board of Governors by George Bush in 2001.

Olson went on to compare Cohn to William Miller, the Carter-era Fed chair whose neglect of rising inflation is thought to have greatly contributed to America’s economic malaise at the time. Only 11 months into his term, the dollar fell nearly 34 percent against the German mark and almost 42 percent against the Japanese yen.

“Miller did not do well,” Olson added.

Miller’s term is widely considered one of the worst of any Fed chairmen.