Joshua Bolton at the OMB said:

"If the final version of this bill that is presented to the president does not include adequate funding levels for presidential initiatives, his senior advisers would recommend that he veto the bill,"

Point being it was not Bush himself who said he would veto it. It doesn't sound like he even know about the suggestion. If it was Bush's idea why didn't Bush say he would veto it himself? Why has he not talked again of the "plan" other than to say it was NASA's ball now?

My view on this is: He tried to co-opt the vision thing from the Democrats (a la JFK). It didn't work he doesn't give a rat's ass for the future and space exploration and exploitation in it. It is a dead issue with him.