Judge Andrew Napolitano said FBI Director Jim Comey "made it worse" for his bureau when he tried to explain his decision-making during the Hillary Clinton email probe.
"He reinforced the criticism that many of us have been advancing," Napolitano said.
"Every time he tries to explain this, he makes it worse," he added.
Napolitano said Comey put rank-and-file FBI agents in the untenuous position of being a part of a presidential election.
He said Comey should never have gone public last July with his recommendation against prosecuting Clinton, and also should never have laid out a public case against her at the same time.
He said Sen. Dianne Feinstein (D-Calif.) was correct in criticizing Comey during a hearing Wednesday, saying it was not his responsibility to do so publicly.
"She makes a strong case [of why] he put his thumb on the scales against [Clinton]," Napolitano said.