Krauthammer actually endorsed John McCain on October 23, 2008, about 10 days before the election. However, he famously penned an OpEd on October 3, 2008 that basically conceded to contest to Obama as not only having run a far better campaign but even as being a reasonable candidate for a liberal. Krauthammer was not alone in his public separation from all things McCain - many conservatives at the time were doing the same if not fully endorsing Obama: i.e. George Will, Colin Powell. It would be difficult to argue that this highly critical statement of 'non-support' for McCain a full month before the election was less effective than the endorsement he gave 10 days before the event.

Nevertheless, I stand corrected. Thank you to tyngsalty at the SeattleTimes for the headsup.