“So that I would say that the problems are more difficult than I had imagined them to be. The responsibilities placed on the United States are greater than I imagined them to be, and there are greater limitations upon our ability to bring about a favorable result than I had imagined them to be. And I think that is probably true of anyone who becomes President, because there is such a difference between those who advise or speak or legislate, and between the man who must select from the various alternatives proposed and say that this shall be the policy of the United States. It is much easier to make the speeches than it is to finally make the judgments, because unfortunately your advisers are frequently divided. If you take the wrong course”

John F. Kennedy: "Television and Radio Interview: "After Two Years — a Conversation With the President" (17 December 1962) http://www.presidency.ucsb.edu/ws/?pid=9060<!-- Online by Gerhard Peters and John T. Woolley, The American Presidency Project -->
1962
Context: There is a limitation, in other words, upon the power of the United States to bring about solutions. I think our people get awfully impatient and maybe fatigued and tired, and saying "We have been carrying this burden for 17 years; can we lay it down?" We can't lay it down, and I don't see how we are going to lay it down in this century. So that I would say that the problems are more difficult than I had imagined them to be. The responsibilities placed on the United States are greater than I imagined them to be, and there are greater limitations upon our ability to bring about a favorable result than I had imagined them to be. And I think that is probably true of anyone who becomes President, because there is such a difference between those who advise or speak or legislate, and between the man who must select from the various alternatives proposed and say that this shall be the policy of the United States. It is much easier to make the speeches than it is to finally make the judgments, because unfortunately your advisers are frequently divided. If you take the wrong course, and on occasion I have, the President bears the burden of the responsibility quite rightly. The advisers may move on to new advice.