Our prior decisions have voiced particular concern with laws that foreclose an entire medium of expression. In this case, we are not persuaded that adequate substitutes exist for the important medium of speech that Ladue has closed off. Displaying a sign from one's own residence often carries a message quite distinct from placing the same sign someplace else, or conveying the same text or picture by other means. As an early and eminent student of rhetoric observed, the identity of the speaker is an important component of many attempts to persuade. An espousal of socialism may carry different implications when displayed on the grounds of a stately mansion than when pasted on a factory wall or an ambulatory sandwich board.
Residential signs are an unusually cheap and convenient form of communication.
Especially for persons of modest means or limited mobility, a yard or window sign may have no practical substitute. Even for the affluent, the added costs in money or time of taking out a newspaper advertisement, handing out leaflets on the street, or standing in front of one's house with a hand-held sign may make the difference between participating and not participating in some public debate. Furthermore, a person who puts up a sign at her residence often intends to reach neighbors , an audience that could not be reached nearly as well by other means. A special respect for individual liberty in the home has long been part of our culture and our law. That principle has special resonance when the government seeks to constrain a person's ability to speak there.