This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Intermediate between ordinary cases of interference with an existing contract, and cases of the prevention of future contracts are cases of existing contracts which can be terminated at the option of one of the parties thereto. The question is then presented whether interference whereby such person is induced to exercise such option is a tort. The weight of authority is that such conduct amounts to a tort if interference with a contract not voidable at the option of the party would be a tort. Thus it is a tort to induce an employer to discharge an employee,1 or to induce an employee to quit work,2 even if there is no employment for any fixed time. So a combination to cause the discharge of one whom his employer could discharge at his pleasure at the end of any week is a tort.3 Where no action lies for causing breach of a contract of employment for an indefinite time it is either because in that jurisdiction no action lies even if the contract is for a definite time,4 or because the discharge is for other reasons not wrongful.5 So a combination to induce or coerce customers to quit dealing with one with whom they have no binding contracts but with whom they are in the habit of dealing is actionable in tort.6 In some states, however, the fact that the party induced to terminate the contract has a legal right so to do prevents conduct of a third person who causes him to terminate it from being a tort, though it would have been a tort had such right to terminate it not existed. Thus A, a vendor of land, had agreed that B might withdraw from the contract for any reason that he saw fit. X, a broker, who negotiated the sale, made false and fraudulent representations to B and thereby induced him to withdraw from such contract. It was held that A had no right of action against B.7
1 Chipley v. Atkinson, 23 Fla. 206; 11 Am. St. Rep. 367; 1 So. 934.
2 Walker v. Cronin, 107 Mass. 555.
3 Lucke v. Trimmers' Assembly, 77 Md. 396; 39 Am. St. Rep. 421; 19 L. R. A. 408; 26 Atl. 505.
4 Baker v. Ins. Co. (Ky.). 64 S. W. 913; Trimble v. Ins. Co. (Ky.), 64 S. W. 915.
5 Lancaster v. Hamburger. 70 O. S. 156; 71 N. E. 2S9 (where the party causing the discharge was a patron of the employer's street railway who made a justifiable complaint of employe's conduct; thereby causing his discharge). Ray-croft v. Tayntor, 68 Vt. 219; 54 Am. St. Rep. 882; 33 L. R. A. 225; 35 Atl. 53 (where the party causing the discharge was in fact a foreman with full power to discharge). 6 Quinn v. Leathern (1901), App. Cas. 495; affirming Leathern v. Craig, 2 Ir. Rep. (1899) 667.