There is always a distinction between the views of educated Americans and the policy of the administration. For example, in 1971, educated Americans opposed the genocide in East Pakistan. But Nixon and Kissinger backed the Pakistan army anyway.
What you need to remember is that the vast majority of American voters are ignorant about the rest of the world and not interested in foreign policy. So, public opinion does not really come into play until American lives are lost. And even then, voters are ignorant. For instance, a majority of Americans believed that Saddam Hussein was behind 9/11.