In the case of Thacker v. Tennessee Valley Authority (TVA), 2018, the U.S. Supreme Court ruled that TVA could be sued for negligence over a power line accident because it was not performing a governmental function at the time of incident. The case arose when Gary Thacker and Anthony Szozda were injured after their fishing boat hit an overhead power line maintained by TVA, resulting in Szozda's death. The court held that while TVA is generally immune from lawsuits due to its status as a government agency, this immunity does not apply when it acts more like a commercial enterprise than a government entity - such as maintaining power lines. This ruling clarified how federal laws shielding government agencies from lawsuits should be interpreted and applied.

In the dissenting opinion for Thacker v. Tennessee Valley Authority, Justice Thomas disagreed with the majority's interpretation of the discretionary function exception in relation to TVA’s activities. He argued that this case should not be about whether a government corporation like TVA is entitled to immunity from suit but rather if its actions fall within a statutory or policy-based exception. In his view, when Congress created entities like TVA and gave them sue-and-be-sued clauses, it intended these entities to operate more like private businesses than traditional federal agencies; thus they should be subject to state tort law unless their actions were specifically directed by statute or policy. Therefore, he would have held that because there was no evidence showing that any federal statute or policy directed how and when TVA employees could move power lines during recreational events on navigable waters - which was at issue in this case - such decisions did not involve an element of judgment based on considerations of public policy and hence did not qualify for protection under the discretionary function exception.