In the McMullen v. Hoffman case of 1898, the U.S. Supreme Court ruled in favor of Hoffman, who was a collector for the Internal Revenue Service (IRS). The dispute arose when McMullen claimed that he had overpaid his taxes and sought to recover $3,000 from Hoffman. However, Hoffman argued that he was not personally liable as he had acted within his official capacity as an IRS agent while collecting these funds. The court agreed with this argument and held that government officials are protected against personal liability when performing their duties unless they have clearly violated established statutory or constitutional rights which a reasonable person would have known about at the time of violation. The ruling reinforced legal principles regarding sovereign immunity - where state entities or employees cannot be sued without consent - and qualified immunity - protecting public officials from lawsuits alleging violations of federal law whilst acting within their professional capacities.

In the dissenting opinion for McMullen v. Hoffman, Justice Harlan disagreed with the majority's decision to uphold a law that allowed states to deny voting rights based on failure to pay poll taxes or other legal financial obligations. He argued that this was in direct violation of the Fourteenth Amendment, which guarantees equal protection under the law and prohibits any state from denying any person within its jurisdiction these protections. Harlan believed that by allowing states to impose such restrictions on voting rights, they were effectively creating a class system where only those who could afford it had access to full citizenship rights. This he saw as fundamentally undemocratic and contrary to American principles of equality and justice for all citizens regardless of their economic status.