“Free college.” Who would object to the idea of giving aspiring scholars a free ride? But as higher education programs are being unveiled in many states across the country, it’s worth asking: What do these programs actually entail?

Currently 16 states administer no-cost college plans based on the “Promise Program” model, a much-lauded initiative in Tennessee launched under the Obama administration. Students can qualify for tuition-free or debt-free financing for a degree program at a state institution (usually the equivalent of two-year community college with the option of transferring to a four-year program). The idea is to remove the burden of post-graduation student debt by covering through a combination of subsidies and grants, nearly all basic tuition and programming fees. Unlike partial scholarships or grants for top students, the program is designed to take care of most or all basic costs and to offer widespread access, akin to regular K-12 education.

This is, of course, a breakthrough in a deeply corporatized, financially unsustainable higher-education system. But researchers at the Century Foundation (TCF) warn of speed bumps in this seemingly righteous quest for free degrees. Although state policy-makers market “community college for all” as the most flexible way to boost the skilled and professional workforce with affordable bachelor’s and associate’s credentials, researchers note that the system “targets aid awards to a population (community college students) that tends to be lower-income and need the support the most.”

So the big promise often comes with reams of fine print: It might include strictly limited income-eligibility criteria and academic-performance standards, or completion or programming requirements that are out of sync with struggling students’ economic capacities.

Often programs require students to be enrolled full-time, which is unrealistic for many low-wage working parents and older students who have no independent source of financial support. Eleven of the 16 programs evaluated were open only to recent high-school graduates—which might automatically exclude people in extreme poverty, the formerly incarcerated, workers with GED qualifications, or recent and undocumented immigrants. Another problem is that if only tuition fees are covered, students would strain to cover additional cost burdens like books, housing, and food (it’s not uncommon on many campuses for undergraduates to be literally going hungry.)

Merit-based or geographical requirements could pose indirect racial, age, or economic barriers. How does a homeless student or an older foster-care youth qualify for a free community-college program that requires years of local residency post-graduation? What about the commuter student forced to move to escape an abusive spouse? One study observed that the interlocking hardships weighing down impoverished communities of color—including “housing quality failures, landlord practices, neighborhood violence, and domestic conflict”—can be barriers to committing to a full degree program, and constrain a student’s long-term housing mobility. The vulnerabilities of chronic deprivation are hard to explain on a college application.

One potential unexpected result of unstable financing, either on the part of the government or the individual student, might be steering students toward lower-level degrees, as a cheaper, faster diploma option.

The question of financial sustainability looms largest for legislators. It’s easier to promise a free degree down the line when budgeting one fiscal year at a time. College Promise programs are typically funded by a hodgepodge of private and public sources, from technology and oil companies to liberal philanthropic trusts, or even state lottery funds. If state budgets are as unstable as poor students’ yearly incomes, a Promise could turn out to be just as precarious, subject to political whims, or the politicized agendas of large donors (like tech companies looking for STEM graduates), all of which could make it nearly impossible to guarantee funding for the duration of students’ long-term degree programs. (Besides, many could suffer from low job prospects even after graduation).

According to the Alliance for Higher Education and Democracy, financial volatility spells educational disruption: “declines in state revenues…increases in tuition, increases in enrollment, and other changes could lead a state-sponsored ‘free tuition’ program to ‘ration’ available financial awards in order to meet demand.”

However, both access and sustainability could be boosted through straightforward reforms. States could scrap merit requirements to include more disadvantaged students and underrepresented communities, according to TCF. They could commit to providing “first dollar” funding, investing an initial tranche as a financial foundation for tuition, so students are not forced to cobble together and balance federal grants and private funds. Some states can discount student funds based on additional subsidies from federal Pell Grants or loans, which could force them into deeper debt and hurt those most in need of support.

The bottom line is that higher education is facing a system-wide crisis, which politicians simply can’t buy their way out of with free-tuition schemes. Co-author of the TCF report Jennifer Mishory points out that, for all the flashy “free-college” programs that states are marketing, “generally…there is also a broader trend going on—higher-education costs have increased over the past few decades and student debt has skyrocketed.” States’ average spending per student has fallen by about 16 percent over the past decade, according to the Center for Budget and Policy Priorities. This includes Tennessee, New York, Kentucky, and Rhode Island, which have all been hyping new Promise-type schemes.

The ongoing erosion of general higher-education investment makes the future of Promise schemes even more uncertain. More federal-budget turmoil lies ahead as the Trump administration’s ruthless cuts to educational funding at all levels and rollbacks on financial aid and subsidized loans come into effect.

Beyond tuition-free courses, students need strong state higher-education systems. As Mishory explains, “if a state is expecting a large boost in enrollment, they should be investing more to ensure there is capacity” with committed educators and support services that help students navigate the higher-education system, especially if they are the first in their families to attend.

A meaningful college experience is not about a “free ride”: It’s about social justice. If Promise programs drive more promising students into debt or force them to drop out because of poverty, the state is destroying the very promise of public education: giving every student a fair chance to realize their highest aspirations.