Chuck Hagel, Obama's nominee for Secretary of Defense.

Fourteen U.S. senators asked President Barack Obama to withdraw his nomination of former Nebraska senator Chuck Hagel, who continues to come under fire for his record on Israel and other areas of foreign policy, for Secretary of Defense.

In a letter dated Feb. 21, the senators—all Republican—said Hagel in his confirmation hearing “displayed a seeming ambivalence about whether containment or prevention is the best approach [to Iran’s nuclear program], which gives us great concern.”

“Any sound strategy on Iran must be underpinned by the highly credible threat of U.S. military force, and there is broad bipartisan agreement on that point,” the senators said. “If Senator Hagel becomes Secretary of Defense, the military option will have near zero credibility.”

The senators also questioned the Hagel nomination based on its lack of near-unanimous support.

“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,” they said. “Over the last half-century, no Secretary of Defense has been confirmed and taken office with more than three Senators voting against him.  Further, in the history of this position, none has ever been confirmed with more than 11 opposing votes.  The occupant of this critical office should be someone whose candidacy is neither controversial nor divisive.”

The letter’s signatories were as follows: Sens. John Cornyn (R-TX), James Inhofe (R-OK), Lindsey Graham (R-SC), Roger Wicker (R-MS), David Vitter (R-LA), Edward Cruz (R-TX), Mike Lee (R-UT), Pat Toomey (R-PA), Marco Rubio (R-FL), Dan Coats (R-IN), Ron Johnson (R-WI), James Risch (R-ID), John Barrasso (R-WY), Tom Coburn (R-OK), and Tim Scott (R-SC).