Among the various instruments in the toolbox of liberalism, the so-called "harm principle," presented as the central thesis of John Stuart Mill's classic "On Liberty," has been one of the most popular. The harm principle has been widely embraced and invoked in both academic and popular debate about a variety of issues ranging from obscenity to drug regulation to abortion to same-sex marriage, and its influence is discernible in legal arguments and judicial opinions as well. Despite the principle's apparent irresistibility, this essay argues that the principle is hollow. It is an empty vessel, alluring but without any inherent legal or political content, into which advocates can pour whatever substantive views and values they happen to favor. Perhaps the major problem that results is that advocates are tempted to advance their values and views not on their substantive merits, but rather by promoting the vessel, or the packaging. And like the harm principle itself, that temptation has proven irresistible - not merely to the office party debater or the talk show host, but to sophisticated philosophers as well, notably including the principle's most articulate proponents: J. S. Mill and Joel Feinberg. All in all, the harm principle serves to confuse and distract, and to permit advocates to gain illicit rhetorical advantage without earning their way. Our public deliberations would accordingly be enhanced if the harm principle were retired from duty.