Sen. Dan Coats, R-Ind., was among 27 Republicans to oppose ending debate Tuesday to vote on the confirmation of Chuck Hagel as secretary of defense.

Coats said in a floor speech that Hagel has “displayed an embarrassing lack of knowledge and confusion” on U.S. policy regarding Iran and that nation’s nuclear intentions.

He said the threat of U.S. military force against Iran “will have virtually zero credibility if Sen. Hagel becomes secretary of defense.”

“It would be unprecedented for a secretary of defense to take office without the broad base of bipartisan support and confidence needed to serve effectively in this critical position,” Coats said about GOP opposition to Hagel’s confirmation.

Fifty-one Democrats – including Sen. Joe Donnelly, D-Ind. – two independents and 18 Republicans supported sending President Obama’s nomination of Hagel to a vote, scheduled for 4:30 p.m. Tuesday.