In general, the evidentiary rule precludes the introduction of evidence of prior or simultaneous negotiations and arrangements that are contrary to the contractual terms of a written contract, if the written contract is to be a complete and definitive expression of the agreement of the parties. A merger clause reinforces the presumption that the written document is complete and final by explicitly establishing that the written document is the final and complete expression of the agreement reached by the parties. Even if, subsequently, the parties agree that they had an interview that, for example, created an “ancillary agreement” that was not included in the original written contract and that the ancillary agreement is contrary to the written contract (for example.B. by changing the date of delivery or the price of a purchase), the additional or deviating terms contained in the subsidiary agreement cannot be applied by the court if the written contract contains a merger clause. In a minority of the United States In the states (Florida, Colorado and Wisconsin), the rule of parol proof is extremely strong and extrinsic proof by blocking its use to interpret a contract. This is called the four-corner rule and is traditional/old. There are two basic rules in the Four Corner case law. First, the court will never allow Parol`s evidence if the parties intend to enter into a full and fully integrated agreement and, second, the court will only turn to parol evidence if the available conditions are totally ambiguous. In other words, evidence before the written contract should not be used to contradict the letter.
To simplify: 1. If the parties plan to fully integrate the contractual conditions, the agreement does not demonstrate a gap. 2. If the parties were considering entering into a partial agreement, no word evidence to the contrary to something integrated shall be permitted. And (3), if Parol`s evidence is security, that is, it is another agreement, and does not contradict the built-in conditions and are not terms that a reasonable person would always naturally incorporate, then the rule does not apply and the evidence is admissible. Parol`s evidence is admissible to demonstrate the existence of grounds justifying the nullity of the contract. These reasons include illegality, fraud, coercion, mistakes and lack of consideration. And Parol`s evidence may show evidence of a lack of contractual capacity. Evidence of childhood, incompetence, etc., would not change the terms of the contract at all, but would show that it is questionable or not. The rule of parol proof is a frequent trap for consumers.
For example, some commentators in California have expressed concern about the Riverisland decision. The new rule will likely make it more difficult to dismiss fraud lawsuits at the start of the litigation. . . .