Barnwell mentions the draconian sentence imposed on spammers by federal anti-spam legislation. The law is clearly unconstitutional since the Constitution nowhere authorizes the feds to regulate such activity. But in principle, in my view, spam is a crime. As found (correctly, in my view) in the now-classic case CompuServe v. Cyber Promotions, “where defendants engaged in a course of conduct of transmitting a substantial volume of electronic data in the form of unsolicited e-mail to plaintiff’s proprietary computer equipment, where defendants continued such practice after repeated demands to cease and desist, and where defendants deliberately evaded plaintiff’s affirmative efforts to protect its computer equipment from such use, plaintiff has a viable claim for trespass to personal property.”

Why is this consistent with libertarianism? Because the owner of property (such as a PC) has the right to control it, which means the right to excluse others from using it. Sending an email to someone is a means of using the PC–it causes things to happen with the PC. It is analogous to knocking on someone’s door. Normally, this is permitted by the owner; and in many contexts, this permission or license is implied by the context. E.g., my neighbor does not trespass if she walks on my sidewalk and knocks on my front door to borrow a cup of sugar. My consent for such innocuous uses of my property is implied. Yet it can be revoked: e.g., I can erect a fence or “no trespassing” sign, or I can tell my neighber she is no longer welcome on my property. If she then knocks on my door she has commited trespass, since she is now using my property without permission.

Similarly in the case of spamming: especially where warned not to spam, someone is using the victim’s computer without their permission; and I would argue there is an implied denial of consent to send unsolicited commercial email, just as there is implied lack of consent for a dozen of my neighbors to hold an Amway meeting on my front lawn.Coda: Gil Guillory’s Mises blogpost, dissent on spam, raises some good points. Gil may like getting spam, but I get probably 300 a day lately, and it is becoming a serious problem. It is not so easy to simply delete them. Second, in a free market, I would envision ways of publicizing your preferences as to whether you do, or do not, consent to receive unsolicited faxes, emails, even mail. After all, when someone shoves a letter in my mailbox I have to dispose of it, which costs. I regard all the tons of snail mail I get as littering on my property.

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