Linguist George Lakoff has written a very interesting article analysing Bush's "stay the course" slogan and why the attempts to change it won't work. Here's an excerpt:

In the context of a metaphorical war against evil, "stay the course" evoked all these emotion-laden metaphors. The phrase enabled the president to act the way he'd been acting - and to demonstrate that it was his strong character that enabled him to stay on the moral path.

To not stay the course evokes the same metaphors, but says you are not steadfast, not morally strong. In addition, it means not getting to your destination - that is, not achieving your original purpose. In other words, you are lacking in character and strength; you are unable to "complete the mission" and "achieve the goal."

"Stay the course" was for years a trap for those who disagreed with the president's policies in Iraq. To disagree was weak and immoral. It meant abandoning the fight against evil. But now the president himself is caught in that trap. To keep staying the course, given obvious reality, is to get deeper into disaster in Iraq, while not staying the course is to abandon one's moral authority as a conservative. Either way, the president loses.

I do hope Lakoff is right. Bush's recent claim that he'd "never been stay the course" is simply laughable. You really should hear Keith Olbermann on that subject. You can do so right here. And while we're at it, you might as well hear Dave Letterman's crack on the slogan right here.