He gave it on December 6th.
http://www.observer.com/2007/romneys-religion-speechHis averages in the polls right before the speech (pollster.com)
Nationally: 12.4
Iowa: 23.0
New Hampshire: 32.4
His averages after the speechNationally: 15.0
Iowa: 24.0
New Hampshire: 32.4
GainsNationally: 2.6
Iowa: 1.0
New Hampshire: 0
This provides some past measure of what kind of effect such a speech has. Now Obama is obviously a far better speech maker than Romney. The msm was behind Giuliani and then McCain at the time while Obama has the msm with him. These are two big advantages Obama has. On the other hand, Obama has the disadvantage of having to explain the inconsistency between his public rhetoric and two decades of private action. All Romney was doing was explaining what his religion was. Either folks accepted it or not. He didn't have to deal we a hypocrisy factor--for once!
There will be a lot of hype about the speech, like there was about Romney's, among the punditry and political junkies. I actually didn't know what the exact affect Romney's speech had before looking at the numbers out of curiosity right now. All I remembered was it was no panacea to the problem he faced on religion. Obama will probably get a slight bump out of this, which will recover some of the damage done by pastorgate. However most folks are only going to see clips of it on the news and he didn't say anything groundbreaking. Has any politician run on an explicit Jeremiah Wright style platform in modern times? Even Reagan didn't explicitly run on racism. Of course presidential candidates are going to talk about the evils of racism. They all do. Folks will recognize that. The people who are being the most mesmerized by his speech already thought he was the savior. This isn't about you. It isn't about folks like me who are not Obama lovers either. It is about everyone in between and history suggests this won't be a magic wand to end the matter.
He does deserve credit, though. While he should have done what he publicly proclaimed during his media blitz a few days ago--spoken out against Wright "if" he knew about his bigotry and nuttiness--during the past two decades he doesn't have a time machine. What he did now is the best thing he can do to cut his losses.
His problem is much bigger than pastorgate, though. He has struggled mightily with whites and women since Wisconsin (and he lost Latinos something like 66-31 in Texas, the only state for which we have any data on Latinos). Ohio, Texas, Mississippi, and Pennsylvania may be aberrations but if they are the vanguard of a trend, and the fact Obama gave this speech suggests the Obama campaign thinks it may be, he is in deep trouble. His biggest problem is inexperience. The "3 am" ad didn't come out of nowhere. The Clinton campaign's polling must have shown this is Obama's most vulnerable spot. He can't cure that problem by taking Presidential 101 over the summer. Everyone already knew he was inexperienced but the ad and subsequent controversy put it front and center. It isn't the only problem he has. Any "new" candidate naturally suffers when he gets some bad press as Obama finally did. It may very well be that what he did while pristine from Iowa to Wisconsin was a peak. Pennsylvania and May will be interesting. This isn't over by any means.