A U.S. appeals court on Thursday, June 27, revived a software engineer’s proposed class action claiming Meta Platforms, opens new tab refused to hire him because it preferred to give jobs to foreign workers who are paid lower wages.

The San Francisco-based 9th U.S. Circuit Court of Appeals in a 2-1 ruling, opens new tab said that a Civil War-era law barring discrimination in contracts based on “alienage” extends to bias against U.S. citizens.

The decision reverses a California federal judge’s dismissal of a lawsuit by Purushothaman Rajaram, a naturalized U.S. citizen who says Meta passes over American workers for jobs in favour of cheaper visa recipients. Rajaram is seeking to represent a class that includes thousands of workers.

Meta, which owns Facebook, Instagram, and WhatsApp, did not immediately respond to a request for comment. The company in court filings has denied wrongdoing and said Rajaram failed to show that Meta intended to discriminate against U.S. workers.

Daniel Low, a lawyer for Rajaram, said that bias against U.S. citizens is a significant problem in the tech industry.

“We expect that this ruling will lead to more lawsuits seeking to end such discrimination,” Low said in an email.

The 9th Circuit had never before addressed whether the federal law, Section 1981 of the Civil Rights Act of 1866, provides protections from hiring discrimination for U.S. citizens.

The only other appeals court that has considered the issue, the New Orleans-based 5th Circuit, said the law does not prohibit bias against U.S. citizens in a 1986 decision. The split created by the 9th Circuit on Thursday raises the chances that the U.S. Supreme Court could take the case if Meta appeals.

Conservative groups have increasingly cited Section 1981, which also bars race discrimination in contracts, in challenging companies’ diversity initiatives and the hiring of foreign visa workers.