Last week, dozens of undocumented high school and college students attended hearings in the Massachusetts state house. They urged lawmakers to extend in-state tuition and state financial aid to all undocumented immigrants who have graduated from Massachusetts high schools, not just those with Deferred Action for Childhood Arrivals (DACA) status.

Several students testified they were forced to give up their dreams of going to college when faced with high out-of-state tuition bills, even though they had arrived in the U.S. as children and attended Massachusetts public schools.

Massachusetts is just one of many states around the country that has grappled recently with the undocumented immigrant population vying for in-state tuition. In Arizona, Maricopa County Community Colleges, fighting to offer their DACA recipient students in-state tuition, have been locked in a legal battle with the state’s Attorney General. In Georgia, the Supreme Court agreed to hear oral arguments in a case against the state’s Board of Regents brought by students with DACA who still have to pay out-of-state tuition.

With the lack of a comprehensive federal immigration overhaul, states have been deciding for themselves whether or not undocumented immigrants can pay in-state tuition at public colleges and universities for more than a decade. At least 20 states currently have policies allowing in-state tuition.

Despite the seemingly increased attention the last few years (especially after DACA granted work authorization to some undocumented immigrants), the question of whether or not undocumented immigrants should be allowed to pay in-state tuition is the product of more than 30 years of policy.

In 1982, the Plyler v. Doe Supreme Court decision made it unconstitutional to deny K-12 public education to undocumented immigrants. Although Plyler v. Doe did not include provisions for higher education, it is considered a major basis of policies on the education of immigrants.

In 1996, Congress passed the Illegal Immigration Reform and Immigrant Responsibility Act (IIRIRA), which included language asserting that an undocumented immigrant cannot receive an education benefit like in-state tuition on the basis of residence in a state unless a U.S. citizen from any state could also receive the benefit.

More recently, the DREAM Act (and its many iterations over the last decade and a half) has drawn attention to a cohort of young undocumented immigrants who face significant barriers to a college education. Most “DREAMers” were brought to the U.S. as children. Many have grown up thoroughly American—attending public schools, speaking English and sometimes feeling more connected to the U.S. than their home countries. But at the end of high school, otherwise college-bound students face steep out-of-state or even international tuition rates.

But some states saw a legal loophole in the in-state tuition provision of IIRIRA. What if eligibility for in-state tuition was determined by something other than residency?

Many states, including immigrant-heavy California and Texas, have passed legislation extending in-state tuition benefits to students who attended and graduated high school in the state. Some critics argue that high school attendance is a de facto measure of residency and should be considered a violation of IIRIRA, but the statute has been challenged and upheld in California’s Supreme Court.

The arrival of DACA in 2012 further accelerated state action on in-state tuition. DACA recipients are given temporary work authorization and a two-year reprieve (with ability to renew) from deportation. Many states, including Massachusetts, Virginia, and notoriously immigrant-unfriendly Arizona, now allow students with DACA status to pay in-state tuition rates.

But for all of the controversy, the number of students benefiting from these policies may not be very high. Even with in-state tuition, college can still be financially out of reach. Undocumented immigrants are not eligible for the federal financial aid that most low- and moderate-income students use, like Pell Grants and federal student loans. Only some of the states offering in-state tuition also offer state financial aid. Demand for private scholarships, like the ones offered by TheDream.us, far outweighs supply.

For the foreseeable future, states will likely continue deciding for themselves. Until Congress acts on comprehensive immigration reform, the legal precedent is such that for DREAMers a state border could be the difference between stopping at a high school diploma and accessing higher education.