The coronavirus outbreak forced students at colleges across the U.S. to finish the spring semester at home. As Congress considers additional relief for higher education, lawmakers should focus on helping students at greatest risk of abandoning their studies altogether.

According to surveys, enrollment in four-year colleges could drop by as much as 20 percent this fall. Attrition among poor and minority students is likely to be worse. Close to two-thirds of minority students say the crisis has changed their higher-education plans, and four out of 10 graduating from high school likely won’t enroll in college this year.

Their hesitation is understandable. Some schools have outlined plans for resuming in-person instruction, but many college students can expect to receive much of their instruction online – an unappealing option for some, and a prohibitive one for those who lack reliable broadband access at home. In effect, the recession has made college even less affordable for low- and middle-income students, requiring them to borrow more to cover expenses like books and food.

For these students especially, choosing to defer or forgo college will be damaging. More than 30 million Americans have some college but no degree. Only 15 percent of the lowest-income students get a bachelor’s degree within eight years of leaving high school. Among dropouts, fewer than 15 percent re-enroll within five years. Students who fail to complete a credential earn less, suffer higher unemployment and are more likely to default on their student loans.

The simplest way to help vulnerable students stay in school is to raise Pell Grants, the federal government’s main form of need-based aid. More than 75 percent of Pell recipients are from families with incomes below $40,000. The maximum annual award of $6,345 for 2020-2021 covers less than one-third of the total cost of attending a four-year public university. Doubling it would cover half the cost for the lowest-income students.

The additional public outlay, at least $30 billion a year, would be substantial, but hardly excessive in the context of the stimulus plans under discussion.

Support for the neediest students should be more flexible, too. Jobless adults and students whose parents are unemployed and in financial difficulty should be eligible for help, like during the last recession. Easing lifetime limits on eligibility would encourage lower-income workers to return to school and complete their credentials. And four-year schools should work with community and technical colleges to make it easier to transfer credits between institutions, so students can get their degrees faster.

Student aid is just one fragment of a much larger problem. American higher education faces a host of other financial challenges, and they’ll demand a sustained and comprehensive government response. But first things first. Right now, Congress needs to help the students most at risk.