Sixty-five universities from 24 states and the District of Columbia, including Harvard, Yale, MIT, Cornell, Duke and Columbia, have signed onto an amicus brief filed last week supporting a legal challenge to a recent immigration policy change.

Amicus briefs, or friend-of-the-court briefs, are legal documents filed by non-litigants with a strong interest in the matter and are meant to advise the court and provide insight.

The policy change in question concerns the calculation of “unlawful presence” for holders of F (foreign students), J (exchange visitors), or M (vocational students) visas and increases the likelihood of students facing three or 10-year bans from the U.S. without warning.

According to the old rule, which had been in place since 1997, students started accruing "unlawful presence" on the day after the government formally found a nonimmigrant status violation or the day after their Form I-94 expired, whichever was earlier.

But a new policy memorandum issued in August changed this. Now students lose their visa status and are technically in the U.S. illegally the day after they stop pursuing their studies or the day after their Form I-94 expires, whichever is earlier.

The colleges argue that while the earlier rule provided everyone with a clear notice of when the "unlawful presence" clock began ticking and gave visa holders a chance to fix the error or to leave the country before the imposition of "devastating" reentry bans, the new rule allows any DHS officer to set a retroactive start date for "unlawful presence."

"Under the new rule, some international students and scholars will face reentry bans for technical and administrative errors of which they were unaware. Others will be forced to leave the country and interrupt their studies for extended periods while discretionary decisions are made regarding their status," says the filing.

American universities are worried that the uncertainty this change brings will make the U.S. a less attractive destination for international students, who are said to have contributed $39 billion to the U.S. economy during the 2017-2018 academic year.

“International students and scholars are vital members of our campus communities and important contributors to our nation,” said John J. DeGioia, Georgetown University President, in a statement released by the non-partisan Presidents' Alliance on Higher Education and Immigration established in 2017. “The talents, perspectives, insights, and passion to serve our world that they bring our campus communities benefits our nation and contributes to the common good that we all share.”

The brief supports the case of Guilford College, et al. against U.S. Secretary of Homeland Security Kirstjen Nielsen in the U.S. District Court for the Middle District of North Carolina, which is calling for a temporary hold on the policy change.

The Trump administration's crackdown on H-1B visa abuse has already led to a drop in students enrolling in U.S. colleges.