Many Democrats thought President Joe Biden’s efforts to forgive vast swaths of student debt would be both good policy and good politics. But their hopes of winning over young voters by relieving college loan burdens did not pan out. The Democratic ticket not only failed to make any gains among 18-to-29-year-olds relative to its 2020 performance but also lost ground in the age group.

Student debt remains a real issue: The $1.6 trillion in federal loans weighing on 42.8 million borrowers acts as a drag on the economy and has trapped millions of Americans in cycles of long-term default. However, Democrats, and everyone else, must learn two lessons from Mr. Biden’s experience: Blanket relief for borrowers, regardless of their income and ability to pay, strikes many voters, correctly, as inefficient and inequitable. And reforming the student debt program is a job best done in the halls of Congress, not the Oval Office.

Mr. Biden’s initial attempt to cancel almost $400 billion in loans — which the Supreme Court rejected — stretched executive power beyond appropriate constitutional bounds. It was also regressive, since it used tax dollars drawn from the general population to subsidize debts freely undertaken by people who gained enhanced earning power as a result. …

After losing at the Supreme Court, Mr. Biden developed a more nuanced plan. His administration shifted toward a program called Saving on a Valuable Education, or Save. This program lowered monthly payments for people on an already existing repayment plan (called Revised Pay as You Earn, or Repaye) and shortened the amount of time that borrowers would need to make those payments before the remainder of the loan was canceled (from 20 or 25 years to just a decade). Those terms were expensive (about $230 billion over a decade, according to the Congressional Budget Office) and too generous: An Urban Institute analysis found that nearly half of bachelor’s degree recipients in the program would pay less than half of their loan. But at least they were better targeted to help student borrowers in need than Mr. Biden’s initial forgiveness ploy.

Still, even this more moderate approach has hit legal roadblocks. Federal judges blocked Save from moving forward after a group of Republican-led states claimed Mr. Biden’s program would deprive them of revenue. In August, the Supreme Court refused to intervene, so the plan is on hold.

Mr. Biden’s plan was always at risk of being torn down by the next Republican administration. And that administration is now at hand, to be headed by President-elect Donald Trump, who has criticized Mr. Biden’s student loan policy as a “total catastrophe” and “unfair” to Americans who already paid off their loans. In Mr. Trump’s first term, he sought to increase monthly payments.

The Biden administration did achieve some of its goals. It canceled more than $175 billion in student debt, primarily by reducing administrative hurdles in the Public Service Loan Forgiveness program, without running afoul of the courts. However, because of the Democrats’ larger political defeat, these policies are now at risk of reversal under a Trump administration.

Mr. Biden’s Save program could be a good starting point for members of Congress to negotiate a more modest income-based repayment system that is fully paid for and targets the neediest, along with other higher-education reforms. Lawmakers should focus on expanding existing tuition assistance for low-income families, emphasizing aid, such as Pell Grants, that does not create future debt burdens.