If history is any guide, not much. Nevertheless, speculation abounds. Over at Political Wire, David
Moore Johnson writes:
bq. Remember, traditionally after a President addresses the nation on an issue we see between a 5% to 10% increase in support.
This is a fantastical statement, one which a reader (who I happen to know is a political scientist) quickly convinced Goddard to correct:
bq. A Political Wire reader emails to say that a systematic study of whether presidential speeches have an impact on poll numbers is reported in the book, On Deaf Ears, and finds shows that in general, major presidential speeches do not lead to a significant shift even in short-term polls.
_On Deaf Ears_, by political scientist George Edwards (here), shows that big presidential speeches have almost no systematic impact on presidential approval. Edwards surveys public opinion before and after every televised presidential speech between 1981-2001 and concludes:
bq. …statistically significant changes in approval rarely follow a televised presidential address. Typically, the president’s ratings hardly move at all. Most changes are well within the margin of error— and many of them show a loss of approval.
But couldn’t this speech be different? Nate Silver thinks so:
bq. The truth is, in fact, that this is a speech the conservatives at the Weekly Standard and elsewhere out to be pretty nervous about. When Bill Clinton delivered his big speech to the Congress on health care 16 years ago, his approval rating shot up by 10 points almost instantenously (sic).
Edwards reports this same 10-point change after Clinton’s speech in September 1993.
But there’s one problem: both Silver and Edwards focus only on Gallup data, and other polls don’t show that same shift. (Silver doesn’t cite a source of data, but I gather it’s Gallup.) Here is a graph of _all_ the presidential approval polls for Clinton in 1993-1994 (courtesy of Roper). I include a smoothed trend line, and highlight the pre- and post-speech Gallup polls in red to show how they are misleading.
The trendline shows no increase in Clinton’s approval immediately after the speech.
Silver argues against a Weekly Standard post by Mary Katherine Ham, who claims that the public has already made up its mind and a speech from Obama is not likely to help. Silver writes:
bq. This argument has it pretty much backward. People like Mary Katherine Ham have heard Obama talk a lot about health care — but that’s because it’s Mary Katherine Ham’s job to pay attention to everything the White House does. It’s not the job of an ordinary voter in Ohio or Florida. And whether design or by poor execution, Obama hasn’t really had a moment that would resonate with those folks. Two thirds people like these are confused about what the Democrats’ health care package actually entails, and are presumably quite willing to get some clarity from Obama.
While the public may not know a lot about specific health care reform proposals, the people _most likely_ to tune into the speech or coverage thereof probably have already made up their minds.
This speech could impact opinion if it drives the news cycle such that the tenor of media coverage shifts away from documenting the loud voices in opposition to portraying some sort of consensus view that reform is necessary, certain reforms favored by Obama or other Democrats will be effective, etc. Only then would a new set of messages filter to less attentive citizens, and that would take some time. In any case, such a consensus doesn’t appear to exist and I suspect that conflict will continue to prove more newsworthy.
So don’t expect the speech to affect the polls much at all. Health care reform is going to be won (or lost) in the backrooms of Capitol Hill, not on network television.
(Hat tip to Matt Grossmann for suggesting a post on this topic.)
UPDATE: See also Gary Langer on the short-lived effects of Clinton’s speech on actual opinion about health care reform. Here again, however, it would be interesting to see more than just ABC’s polls, especially since their “post-speech” data is based on a single poll conducted “the night of his address to the nation.”