claim must allege a breach “of some positive legal duty imposed by law because of the relationship of the parties, rather than from a mere omission to perform a contract obligation.” Ibid, (quoting Battista v. Lebanon Trotting Assoc., 538 F.2d 111, 117 (6th Cir.1976)). In a case where, as here, “the causes of action in tort and in contract are factually intertwined, a plaintiff must show that the tort claims derive from the breach of duties that are independent of the contract and that would exist by force of law notwithstanding the formation of the contract.” Ibid, (internal quotation marks and citation omitted).
As adopted by Ohio courts, “[t]he parol evidence rule states that ‘absent fraud, mistake or other invalidating cause, the parties’ final written integration of their agreement may not be varied, contradicted or supplemented by evidence of prior or contemporaneous oral agreements, or pri- or written agreements.’ ” Galmish v. Cicchini, 90 Ohio St.3d 22, 734 N.E.2d 782, 788 (2000) (quoting 11 Williston on Contracts 569-70, § 33.4 (4 Ed.1999)). The parol evidence rule is not a rule of evidence, but one of substantive contract law, whose “principal purpose is to protect the integrity of written contracts.” Id. at 789 (citation omitted). Thus, it bars consideration of extrinsic evidence not “for any of the reasons ordinarily requiring exclusion, based on the probative value of such evidence,” but “because [extrinsic evidence] cannot serve to prove what the agreement was, this being determined as a matter of law to be the writing itself.” Ibid.
The parol evidence rule does not serve to bar extrinsic evidence under all circumstances. The limits to its effect are already contained within Williston’s formulation of the rule, which was adopted by Ohio courts: the rule will not compel exclusion of evidence when there is “fraud, mistake or other invalidating cause,” and it will not compel exclusion of evidence that does not “var[y], contradict[] or supplement ]” an integrated written agreement. Ibid. In general, whether the parol evidence rule bars extrinsic evidence depends on the purpose to be served by that evidence in a particular case. “When two parties have made a contract and have expressed it in a writing to which they have both assented as the complete and accurate integration of that contract, evidence ... of antecedent understandings and negotiations will not be admitted for the purpose of varying or contradicting the uniting.” Ed Schory & Sons v. Francis, 75 Ohio St.3d 433, 662 N.E.2d 1074, 1080 (1996) (quoting 3 Corbin, Corbin on Contracts (1960) 357, Section 573) (emphasis added). However, “[i]n accordance with well established rules ... parol evidence [i]s admissible for the ‘purpose of clarifying an ambiguity in the language used” in a contract. Charles A. Burton, Inc. v. Durkee, 158 Ohio St. 313, 109 N.E.2d 265, 271 (1952) (emphasis added). And, most pertinent to the instant case, pursuant to the “fraud exception,” “the parol evidence rule does not prohibit a party from introducing parol or extrinsic evidence for the purpose of proving fraudulent inducement.” Galmish, 734 N.E.2d at 789 (emphasis added).
Its name notwithstanding, the “fraud exception” to the parol evidence rule has been interpreted by Ohio courts to encompass other “invalidating causes” beyond actual “fraud.” See Galmish, 734 N.E.2d at 788 (parol evidence rule applies “absent fraud, mistake or other invalidating cause”) (emphasis added); see also Clemente v. Gardner, No.2002-CA-00120, 2004 WL 953700, at *6 (Ohio App. 5 Dist. Apr. 26, 2004) (stating that the parol evidence rule does not forbid proof of fraudulent inducement or negligent misrepresentation); Brothers v. Morrone-O’Keefe Development Co., LLC, No. 03AP-119, 2003 WL