Students who start college next year will get the benefit of the more generous income-based repayment program. But they will look longingly at recent graduates who got better repayment terms and $10,000 knocked off their debt. They will correctly point out that this is unfair – after all, tuition is still rising, so they're even worse off than their predecessors! They will badger Democratic politicians to help them out, too.

Democrats are putting themselves in the same position as those who kept passing "doc fixes": This first action will beget demands for a second and a third. Because this isn't going to cure the underlying drivers of excessive tuition growth, any more than the "doc fixes" fixed the problem of soaring health-care costs.

The student loan program itself represents an attempt to solve the problem of rising college costs, and the theory seems sound enough. After all, kids who went to college would eventually earn a lot more money than they would have otherwise, and loans let them monetize some of that future income to pay their tuition.

But, of course, tuition prices were already partially based on the expectation of higher future incomes, and all that future income shifted backward in time meant colleges could charge even more. One study suggests that when Congress raised the caps on subsidized federal loans, as much as 60 cents of every extra dollar lent got eaten up by tuition increases. Which in turn ballooned loan balances, and in turn created political pressure to make student loan programs more generous to borrowers – as the government has over the years, undoubtedly putting further upward pressure on tuition.

Trying to fix these problems by making it even more attractive to borrow money is like trying to quit smoking by switching to unfiltered cigarettes. When you're doing something destructive, your best bet is to stop. But if you can't manage that, you should at least refrain from making the problem worse.