You can make a difference. Bush listened to conservatives who were angry over government spending in the spring. Bush is not the type of person who, after winning reelection, is going to flip the bird at conservatives since he doesn't have to worry about another reelection. Bush has a broad, conservative agenda laid out for the next term, and cracking down on illegal immigration is one of them.
How can you be so sure? It's not been top of mind in this administration so far. And sure, terorism and Iraq have been a distraction. But I don't think that's going to change anytime soon. And leaky borders should have already been a terrorism issuea already.
If he does, I will apologize, but don't expect me to hold my breath.