When I emphasize that presidential speeches have limited effects, I don't want to overplay the point. One point here is that if I'm talking about the speech, I'm talking about just that: the effects of the speech by itself -- especially the effects of the speech on public opinion, or more broadly on the question of whether a speech can affect Congressional action by changing public opinion which then in turn affects what Congress will do. There's good reason to believe that in that sense presidential speeches have very limited possibilities.
But of course the president did more than just give a speech yesterday; he also offered a new initiative, one that has both legislative and administrative components. And that can certainly matter, regardless of whether the speech has any effect. So while I understand the impulse to minimize presidential control -- indeed, that's usually where I come down on these things -- it's also possible to overdo it. What got me started on this is what Ezra Klein said:
That got to the essential truth behind the speech: all the president can do is ask Congress to pass his bill. The only direct leverage he has is his ability to make the ideas popular and their refusal unpopular. He can’t make them pass the bill. He can’t pass it himself. He can’t use an executive order. He can propose ideas and use the bully pulpit to force them onto the agenda. After that, it’s up to Congress.That's I think too strong. It's true that there's nothing Obama can do to force Congress to act. But there's a very large gap between merely putting it on the agenda and forcing them to act. The president certainly can fight for bills he cares about, and he can use all of the many tools at his disposable in that fight -- tools such as vetoes (or threatened vetoes) on Congressional priorities, or appointments, or the use of administrative options.
One of the reasons for presidents to give high-profile speeches, indeed, is to signal to Congress (and to everyone else in the policy-making process) that this is something that's a high priority for him. This is something he intends to fight for, and that he's willing to bargain for. And if that's true -- if Obama is in fact willing to give way on GOP priorities if they're willing to accept some of what he's proposing -- then this thing does in fact have some chance of being enacted. But that's (mostly) an inside game. It's not about barnstorming the nation to convince people to put pressure on their Members of Congress; it's about trying to find some way of getting to a trade that both sides can be happy about (while also finding pressure points that can be used to help push rank-and-file Members to go along). Again, thought of in that way, the function of the speech is mostly to clearly let everyone know that the president intends to be very aggressive in doing all of that.
I should also mention that yet another effect of these high-profile speeches can happen before they're even given. Announcing a high-profile speech that will contain a new legislative program can be an excellent way of focusing the attention of people within the administration on this particular presidential priority. Remember, resistance to the president doesn't just come from Congress; it also comes from executive branch departments and agencies, which for all sorts of reasons (good and bad) have their own agendas and can often win battles with the president. Publicity and deadlines are two weapons the president can use to pressure them to cooperate.
So all in all I don't want to give the impression that what happened yesterday can't be important; it can. It's just that the way that it's important is rarely through enlisting public opinion to force Congress to do stuff; mostly, neither step of that really works. But again, just because the president is not all-powerful doesn't mean that he can't at least potentially wield quite a bit of influence.