I think that Bush will have to come out with some sort of statement about his support for the 2nd Amendment before he gets the endorsement of the NRA. Maybe sometning like:
"During the past ten years, there was absolutely no change in crime that could even remotely attributed to the Assault Weapon Ban. Even before that, statistics show that assault weapons WERE NOT the preferred weapon of choice by criminals and were used in less than 1/10 of 1% of all violent crimes,
The vast majority of gun owners, well over 99%, are good law-abiding, hard working, citizens who are conscientious about the safety of their family, their neighbors, and their country. Prohibiting the ownership of a gun that is functionally no different from many guns over 100 years old will do nothing to deter crime but will unnessarily infringe upon their right to keep and bear arms as guaranteed by the Constitution of the United States.
For these reasons, it is my belief that there is no need to renew the Assault Weapon ban."
If he wanted to say that, he could have said it months or years ago. The mandated by law study, which showed the ineffectiveness of the ban, was completed some time ago, IIRC. He's just hoping the issue goes away without him having to act one way or the other.
But if by some Satanic miracle the ban should pass Congress. He should veto it, out of political pragmatism if for no other reason. Vetoing, even a pocket veto would be fine, it won't lose him many votes that he would have gotten anyway. Signing it *will* lose him a pot-full of votes (and good campaign workers as well) that he would have otherwise gotten. If he and his political advisers have any sense at all, he will not sign the bill, and then he will make a statement similar to what you postulate, it could even simpler. "I changed my mind because the study showed the ban was not effective in reducing crime".