The Slaker v. O'Connor case in 1928 involved a dispute over the validity of a will and testament. The plaintiff, Slaker, was an administrator who challenged the legitimacy of a will that left property to the defendants, O’Connor et al., claiming it had been procured through undue influence. However, he failed to provide substantial evidence supporting his claim during trial proceedings at lower courts which led them to rule in favor of the defendants. Upon reaching Supreme Court level on appeal by Slaker, it was held that there were no errors committed by lower courts as they correctly applied Minnesota law regarding burden proof for undue influence claims. It stated that unless clear and convincing evidence is presented showing coercion or manipulation affecting free-will execution of testator's wishes; mere suspicion or possibility isn't enough to invalidate such documents. Therefore, Supreme Court affirmed previous rulings upholding legality and enforceability of said will - thereby denying relief sought by plaintiff.

The dissenting opinion in the case of Slaker, Administrator v. O'Connor et al., argued that the majority's decision to uphold a lower court ruling was incorrect because it failed to consider important aspects of contract law. The dissenting justices believed that there was no valid contract between the parties involved due to lack of mutual assent and consideration. They contended that an agreement made under duress or without full understanding cannot be legally binding, as it violates principles of fairness and equity. Furthermore, they disagreed with the majority's interpretation of "consideration," arguing that mere acknowledgment or promise does not constitute sufficient legal consideration for a contract unless something valuable is exchanged between parties. Thus, they felt this case should have been remanded back to trial court for further examination instead of affirmatively upholding its judgment.