Because having McKrazy an enemy would have been a big pain in the @ss. I suppose President Bush thought the SCOTUS would knockdown the BS McCain-Feingold.
If I recall correctly, McCain-Feingold barely passed 5 to 4. This illegal law may not be able to stand another challenge with Alito and Roberts on the Supreme Court.
And in the Senate I think it was the usual suspect RINOs that joined the 'rats so there was no fear of a veto.
Bush needs to set this thing right...and now.