I've been involved in a number of pretty desperate attempts to try and keep a drug conviction off some kid's record so he can continue to attend school. However, I must admit that I view this as a long shot. I'm pretty sure the constitutional crimlaw issues will be judged not to apply because financial aid is a civil rather than a criminal issue. As for the equal protection claims, acting prejudicially against those who have been convicted has a long history (denial of voting rights, denial of right to have a firearm, denial of right to hold office, etc.) and I doubt this will give the courts much pause.
I understand the basic idea behind the federal legislation denying aid to those who have been convicted of drug use. If the young adult understands that he will lose the money he needs to go to college he has an incentive not to use drugs. Of course, that assumes people know about this provision and that a drunk college freshman will remember it at 2 a.m. Honestly, neither is too likely.
Still, one should be responsible for one's actions. However, the truly galling part about this is, as I understand it, this is a lifetime ban. That's just downright stupid. A two year ban would make the point and perhaps not totally throw a kid who got caught doing something dumb entirely off track. Maybe the ban should go as long as 5 years; this would give someone who has changed his life a chance to come back later and improve it. Anyone who's seen much of life knows that a lot of the things which are done 18-22 are not things which those who have grown a little have a desire to do at 30. A lifetime ban just tells someone that no matter how much he improves himself he will still be denied the opportunity to go to college (unless he somehow increases his financial lot without college, at which point this law become irrelevant anyway)..