As the writeups above have pointed out, George W. Bush doesn't have the ability to grant a pardon from the death penalty, so blaming him for the issue doesn't really make sense. However, there is one point which hasn't been brought up here yet, and I think it does need to be mentioned.
There is a reason Texas has a higher than normal number of executions. In Texas, juries do not have the option of sentencing a convicted criminal to life without possibility of parole. So the only way one can insure that a criminal will never again be a menace to society is to sentence him to death.
Why is this? I have no idea. However, even though I support the death penalty, I feel juries should at least have the option of sentencing a criminal to life without parole. After all, there are people who are so strongly against the death penalty that they wouldn't want someone who murdered them or their loved ones to be sentenced to death. These people should have some assurance that the criminal will never again be allowed to harm them or anyone else, and that he will spend the rest of his life in a cell.
So is this Bush's fault? Not directly, as I see it. Sure, if he felt strong enough about it, he could suggest that the legislature allow a life without parole sentence. Even that wouldn't guarantee it would happen, though. The only way this would change is for the people of Texas to become concerned enough to evoke the attention of the state legislature, which isn't likely to happen. After all, most Texans are death penalty supporters