His conclusion? Some recent changes to Google's search algorithms might be behind the change, but that doesn't mean Google wasn't feeling the heat and found a way to resolve it without uniquely targeting spreadingsantorum.com.
To date, Google has refused to make any change specifically to the listing, which is pretty much in keeping with how it approaches these types of issues.
Instead, Google prefers to resolve tricky issues like these by looking for solutions that may impact a wide range listings. Rather than only fix how President George W. Bush was “Google bombed” to rank for “miserable failure,” Google rolled out a fix to solve Google bombs in general.
In the end, unless Google just comes out and says so, it's very hard to know whether this was targeted or not. Changing the system the way they do could provide very good cover for getting rid of problematic rankings without singling out a particular site, but of course their algorithms are fine-tuned all the time for perfectly legitimate reasons, with thousands of sites finding their rankings suddenly altered.
Sullivan says he's checking with Google for further info, stay tuned.