(CNN) President Donald Trump's comment that he's willing to meet with Iranian President Hassan Rouhani with no preconditions shows diplomatic over-confidence, a Democratic lawmaker on the House Armed Services Committee said Monday.

During a joint news conference at the White House alongside Italian Prime Minister Giuseppe Conte, Trump said that he would meet with Iranian leaders "whenever they want to" with "no preconditions."

California Democratic Rep. John Garamendi said such a meeting would likely not be successful.

"I don't know what the President hopes to achieve with that meeting," he said in an interview with CNN's Wolf Blitzer on "The Situation Room." "If the President's going to sit down with them without any preconditions, he must think he's a genius, because if he thinks he can pull off a meeting with the supreme leader of Iran without any prior discussions -- good luck."

Blitzer corrected Garamendi that a hypothetical meeting would likely not be with Iran's supreme leader, Ayatollah Seyyed Ali Khamenei, but with Iranian President Hassan Rouhani.

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