WASHINGTON (Reuters) – U.S. Democratic Senator Joe Manchin of West Virginia said on Tuesday he would vote against the nuclear deal with Iran, even though U.S. President Barack Obama already has enough Senate support to protect the agreement.

“I believe that to be a super power, you must possess super diplomatic skills, and I believe that we can use these skills to negotiate a better deal,” Manchin said in a statement.

U.S. Senator Joe Manchin (D-WV) (R) talks to reporters outside of a closed-door Senate Armed Services Committee briefing on the Bergdahl prisoner swap at the U.S. Capitolin Washington June 10, 2014. REUTERS/Jonathan Ernst