The controversy springs from a question at the YouTube debate asking whether Obama would be willing to meet, without precondition, with the leaders of Iran, Syria, Venezuela, Cuba and North Korea.
Obama, an Illinois senator, said he would and called it a break with the Bush administration's diplomatic policies.
Clinton, in the debate, said she would pursue vigorous diplomacy but she wouldn’t make such a promise without knowing the other countries’ intent.
“I don’t want to be used for propaganda purposes,” she said.
In a telephone interview today, the New York senator went further. Of Obama’s comment, she said: “I thought that was irresponsible and frankly naive.”