The Supreme Court on Wednesday lifted a legal barrier to a lawsuit brought by a veteran wounded in Afghanistan by a suicide bombing, ruling that a contractor can face state-law claims when a plaintiff alleges supervision failures rather than simply being swept under wartime immunity.

The case involves former Army Spc. Winston Hencely, who was injured in 2016 when he confronted Ahmad Nayeb after the attacker had been able to get close to him at a Veterans Day weekend 5K race at Bagram Airfield. According to court documents described in the ruling, Nayeb then blew himself up, killing five people and injuring more than a dozen, and the blast left Hencely with severe injuries, including damage to his skull and brain and lasting neurological and other effects described by his lawyers.

In the Supreme Court decision, the justices addressed whether Fluor Corporation, the engineering and construction company that employed Nayeb, could avoid the lawsuit on grounds that it was working for the federal government during wartime. Hencely sued Fluor in South Carolina, where two of Fluor’s subsidiaries are based, alleging claims including negligent supervision, negligent entrustment of tools and negligent retention of an employee.

Fluor argued that it could not be sued while performing work it said was tied to wartime federal contracts, which are generally shielded from lawsuits. The Supreme Court disagreed with that framing, concluding that the company’s alleged failure to carry out its duties in supervising Nayeb was central to whether Hencely’s claims could proceed.

Writing for the majority, Justice Clarence Thomas explained that companies are protected when they are fulfilling government contracts, but that protection did not extend to the supervision lapse alleged by Hencely. The opinion described an Army investigation faulting Fluor’s failure to supervise an Afghan employee who built the vest on site inside the base.

The court’s ruling came by a 6-3 vote. Thomas was joined by Justices Sonia Sotomayor, Elena Kagan, Neil Gorsuch, Amy Coney Barrett and Ketanji Brown Jackson. Justices Samuel Alito, John Roberts and Brett Kavanaugh dissented, with Alito writing that the lawsuit risked intruding on wartime powers and decisions, including a policy the dissent said required contractors to maximize employment of Afghans.

The case returns Hencely’s claims to the lower-court process, giving the lawsuit another chance to proceed on the allegations that Fluor’s supervision practices failed to prevent the attack that left him wounded.