The Oregon Legislature has unanimously decided to explore the “Pay it Forward” concept for college tuition. The idea is that students would go to college for free, and then pay for it with a percentage of their income for the next 20-25 years.

The costs and risks of the concept are so massive that the move can only be understood as a sign of our widespread desperation about college costs and debt. In Oregon, we also have the pressures of the governor’s 40-40-20 plan, which sets the highest value on awarding more degrees, assuming that 80 percent of high school graduates need some sort of advanced degree or certificate.

House Bill 3472, which the governor is expected to sign, instructs the state’s Higher Education Coordinating Commission to design a pilot project to test the Pay it Forward idea, which originated at a Seattle nonprofit and was brought to the Legislature by Portland State University students.

Although the approach is supposed to be self-sustaining eventually, the cost to get there is estimated to exceed $9 billion. That’s shocking enough by itself, but the bigger danger is unintended consequences, about which we can make only limited guesses.

Here’s one: Pity the programs that don’t lead to high-paying jobs. If the fund gets repaid based on the graduate’s income, you can be sure that programs such as literature and social-worker training will struggle for support from cash-strapped university administrations. Engineering and high finance, on the other hand, would be in line for disproportionate investments.

In takes only a cursory look at history to see a prime related example. When the federal government made student and parent loans easy to get, it freed colleges and universities from normal market forces. Many analysts believe that’s a major factor in the surge of college costs. It was a well-intentioned move to level the economic playing field, but it had unanticipated and severely damaging effects.

Pay it Forward ducks the fundamental questions about whether higher education should cost what it does, and also which students benefit from going to college.