To take an issue away from Mcain-Feingold. If he vetoed it Mcain and the demos have an issue. Now McCain will be quiet as this goes court and hopefully be shot down and what's McCain going to do then? Trash the Supreme Court?
The press would have a field day if he vetoed.
BTW, joe sixpack doesn't really care about this and that 78% figure you saw was an online poll, which is not scientific or accurate.
In the last month it appears Bush has taken away 90% of the demos' issues. Soon they'll have nothing to run on in 2002/04, because Bush will have coopted the majority of their platform. That'll be great, huh?