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.
Undue influence has been said to consist of compulsion insufficient to constitute technical duress,1 The same idea, differently expressed, is that "duress is but the extreme of undue influence.",2 Undue influence has been said to be distinguishable from duress in being only a social, moral or domestic force.3 Facts which in most states would be held to amount to duress are said in others to avoid the contract for undue influence.4 Thus where a married woman signed a contract for her separate maintenance and a release of her dower and homestead rights because while sick she had been treated by her husband in a cruel manner, locked in her room, and finally taken to a strange place and ordered to sign, it was said that the contract was voidable because she signed under an undue influence which amounted to a moral duress.5 A contract or conveyance induced by threats of criminal prosecution, either of the party or of those in near relations to him, is said in many states to be induced by duress.6 On the other hand, such facts have been said not to amount to duress, but to undue influence.7 Thus contracts, morttable principle which renders voidable contracts obtained by undue influence." Adams v. Bank, 116 N. Y. 606, 15 Am. St. Rep. 447, 6 L. R. A. 491, 23 N. E. 7.
L. ed. 112; Bell v. Campbell, 123 Mo. 1, 45 Am. St. Rep. 505, 25 S. W. 359; Erwiu v. Hedrick, 52 W. Va. 537. 44 S. E. 165; Delaplain v. Grubb, 44 W. Va. 612, 67 Am. St. Rep. 788, 30 S. E. 201.
15 Seward v. Seward, 59 Kan. 387, 53 Pac. 63.
16Gillis v. Smith, 114 Miss. 665, 75 So. 451.
1 Edwards v. Bowden, 107 N. Car. 58, 12 S. E. 58. "Pressure which does not amount to duress at common law may be considered in equity sufficient to set aside or resist a contract-" Lomerson v. Johnston, 44 N. J. Eq. 93 [quoted in Colonial Building & Loan Association v. Griffin, 85 N. J. Eq. 455, 96 Atl. 901].
2 (Commercial) National Bank v. Wheelock, 52 O. S. 534, 551, 40 N. E. 636.
3Munson v. Carter, 19 Neb. 293, 27 N. W. 208.
4 Haydock v. Haydock, 33 N. J. Eq. 494, 38 Am. Rep. 385.
5Willetts v. Willetts, 104 111. 122.
6Bank v. Croco, 46 Kan. 620, 26 Pac. 939; Thompson v. Niggley, 53 Kan. 664, 26 L. R. A. 803, 35 Pac. 290; Heaton v. Bank, 59 Kan. 281, 52 Pac. 876; Morse v. Woodworth, 155 Mas. 233, 248, 27 N. E. 1010, 29 N. E. 525; Miller v. Lumber Co., 98 Mich. 163, 39 Am. St. Rep. 524, 57 N. W. 101; Insurance Co. v. Hull, 51 O. S. 270, 46 Am. St. Rep. 571, 25 L. R. A. 37, 37 N. E. 1116.
7Bell v. Campbell, 123 Mo. 1, 45 Am. St. Rep. 505, 25 S. W. 359. "It is not an accurate use of language to apply the term duress to the facts upon which the plaintiff seeks to recover. The case falls rather within the equigages, and the like, caused by a threatened arrest of the party himself,8 or of a son,9 or a husband,10 have been held voidable on the ground of undue influence.