The devolution of Presidential rhetoric, perhaps starting with the very notion of TR's "bully pulpit," much less the theater of the modern State of the Union, demonstrates the problem he confronts fully. The executive is not constructed to speak, but to act. If he speaks, his speech must result in effective action. It is tempting to say that in a country where popular opinion is everything, the President's power to persuade is his most effective action. Thus, the "bully pulpit," the televised State of the Union, the press conferences, the Presidential reading lists, the campaign books, etc. etc. are not a product of politics merely trying to give Oprah competition. Rather, the President could be doing his job in being a second-rate media figure.
All one has to do, though, to demolish the argument that the President's primary power lies in persuasion is focus on what an inability to persuade does to effective action.