Is a covenant in restraint of a particular trade and unlimited as to space against public policy and therefore void and unenforceable? Long ago an English judge, in speaking of the making of contracts, protested against arguing too strongly upon public policy. "It is a very unruly horse, and, when once you get astride it, you never know where it will carry you."1 Right he was and is, and the judge who would keep his saddle must be a good rider, for the horse shies badly on the way at every new condition in trade and commerce, occasioned by recent developments in steam and electricity and their increasing use as agencies in communication and transportation. A rule of law is no sooner announced on the subject of public policy than we find by judicial determination that the rule is no longer adapted to the altered condition of things. No class of contracts illustrates this more forcibly than contracts in restraint of trade. The decisions of courts upon the policy of the law regarding such contracts and as to what is and what is not a reasonable limitation as to time and space are truly bewildering. We do not intend to discuss, or even refer to many of the older cases-and there are many on the subject-but to observe the judicial tendencies in the last few years in relation to the contracts in restraint of trade wherein the restraint is practically unlimited as to space, and to note how far the courts have veered away from rules long regarded as settled law; and followed what has been termed the "new doctrine."
Knowlton, Jerome C. "New Doctrine Concerning Contracts in Restraint of Trade." Mich. L. Rev. 8, no. 4 (1910): 298-313.