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.
If a combination of persons, acting in conspiracy, attempts to compel one person to break a contract with another, a question is presented which in some respects is different from that in which one person induces, or compels, a breach of contract; since threats made by a number of persons, or by one person who controls a number of persons, may involve consequences very different from threats made by a single person.1 Probably, however, if bona fide persuasion alone were resorted to, the effect of persuasion by several acting in concert would not be substantially different as to its legal effect from persuasion by one. A combination of persons, to induce a breach of contract, usually, however, resorts to some form of compulsion when persuasion fails. At any rate the reported cases on this branch of the subject involve the idea of compulsion in general. Thus where a number of tailors stopped work and sent back in an unfinished condition the work on which they were engaged, knowing that under the circumstances it would be impossible for their employer to get men to finish it, such conduct was held to amount to a tort.2
3 See ante, this section.
4 Payne v. Ry., 13 Lea (Tenn.), 507; 49 Am. Rep. 666.
5 Heywood v. Tillson, 75 Me. 225; 46 Am. Rep. 373.
6 Passaic Print Works v. Dry-Goods Co.. 105 Fed. 163: 62 L. R. A. 673; 44 C. C. A. 426.
1 Quinn v. Leathern (1901), App. Cas. 495; affirming Leathern v. Craig, 2 Ir. Rep. (1899), 667.
2 Mapstrich v. Ramge, 9 Neb. 390; 31 Am. Rep. 415; 2 N. W. 739.