Ron Paul was booed for advocating it, but a past president said much the same thing in a bygone State of the Union address.

After Ron Paul was derided for saying in a GOP debate that we should practice the Golden Rule in foreign policy, doing unto other nations as we'd have them do unto us -- a suggestion that drew boos from the crowd -- Uri Friedman and Daniel Larison note that a past president, Millard Fillmore, advocated that very approach in his first State of the Union Address in December 1850:

Among the acknowledged rights of nations is that which each possesses of establishing that form of government which it may deem most conducive to the happiness and prosperity of its own citizens, of changing that form as circumstances may require, and of managing its internal affairs according to its own will. The people of the United States claim this right for themselves, and they readily concede it to others. Hence it becomes an imperative duty not to interfere in the government or internal policy of other nations; and although we may sympathize with the unfortunate or the oppressed everywhere in their struggles for freedom, our principles forbid us from taking any part in such foreign contests. We make no wars to promote or to prevent successions to thrones, to maintain any theory of a balance of power, or to suppress the actual government which any country chooses to establish for itself. We instigate no revolutions, nor suffer any hostile military expeditions to be fitted out in the United States to invade the territory or provinces of a friendly nation. The great law of morality ought to have a national as well as a personal and individual application. We should act toward other nations as we wish them to act toward us, and justice and conscience should form the rule of conduct between governments, instead of mere power, self interest, or the desire of aggrandizement. To maintain a strict neutrality in foreign wars, to cultivate friendly relations, to reciprocate every noble and generous act, and to perform punctually and scrupulously every treaty obligation -- these are the duties which we owe to other states, and by the performance of which we best entitle ourselves to like treatment from them; or, if that, in any case, be refused, we can enforce our own rights with justice and a clear conscience.

What once was literally presidential is now regarded as discrediting. (It should be noted that Fillmore, like so many presidents before and after him, did not live up to his lofty words, and that apart from foreign policy he was implicated in the awful slavery-extending policies of his era.)