In the case of US Airways, Inc. v. Robert Barnett (2001), the U.S Supreme Court had to decide whether an employer's policy of seniority-based job assignments could be overridden by a disabled employee's request for reasonable accommodation under the Americans with Disabilities Act (ADA). Robert Barnett, who was injured while working as a baggage handler and consequently transferred to a less physically demanding mailroom position, faced displacement from his new role due to more senior employees choosing it during their transfer period. He requested that he remain in his current role as an ADA accommodation but was denied by US Airways because it would violate their seniority system. The court ruled 5-4 in favor of US Airways stating that ordinarily, an employer’s showing that a disability-related reassignment conflicts with the rules of a seniority system will be sufficient to demonstrate that 'accommodation' is not 'reasonable'. However, they also noted exceptions might occur if there were special circumstances undermining the company's claim.

In the dissenting opinion for US Airways, Inc. v. Robert Barnett (2001), Justice Souter argued that a reasonable accommodation under the Americans with Disabilities Act (ADA) does not necessarily have to be consistent with an employer's disability-neutral rules or policies. He disagreed with the majority's view that seniority systems should generally take precedence over ADA accommodations, stating that such a blanket rule is inconsistent with Congress' intent in passing the ADA and overly restricts courts' ability to consider individual circumstances on a case-by-case basis. Instead, he proposed that courts should weigh various factors including hardship on both parties involved when determining whether an accommodation is reasonable or not.