Why cant school loans be discharged in bankruptcy?

School loans are given to students who do not even have a credit rating. No bank in their right mind would loan a penny to them. If they could be discharged by bankruptcy students would go bankrupt when they graduated to get rid of the loans. The only way the government can have a chance of getting the money back is to make it so students cannot discharge it by bankruptcy. If you can get a private loan, which most students cannot, it can be discharged by bankruptcy. It is not fair to the American public who pay for the students to go to school to have them discharge it.