President Biden has announced a plan to forgive between $10,000 and $20,000 in federal student loans for tens of millions of borrowers. The scheme will cost more than $300 billion and benefit mostly college-educated households that don’t need the help. But its most pernicious consequence is the precedent it sets. Colleges are sure to exploit the promise of repeated cancellations by hiking tuition and opening new degree programs of questionable value.

The federal government is on track to disburse $1 trillion in new student loans over the coming decade. The Committee for a Responsible Federal Budget estimates that it will take less than a decade for the outstanding stock of student loans to climb back to its current level. Candidates in the next Democratic presidential primary will try to one-up each other with new promises of forgiveness.