Undue influence is the most frequently litigated ground for challenging a California trust or will, and for good reason. The circumstances that produce undue influence, a vulnerable elderly person in close contact with someone who benefits from influencing their estate plan, are common in California’s aging population, and the consequences, a complete reallocation of an estate from intended recipients to the influencer, are among the most significant wrongs the probate system is called upon to address.
But proving undue influence in court is genuinely difficult. The influence occurs in private. The primary witness, the decedent, is not available to testify. The influencer typically has a plausible innocent explanation for every specific action that is questioned. Understanding how California courts analyze undue influence claims, what evidence is required to prove each element, and how California’s statutory presumption can shift the burden of proof is the foundation for any California trust contest based on this theory.
The Definition of Undue Influence Under California Law
California Welfare and Institutions Code Section 15610.70 defines undue influence as excessive persuasion that causes another person to act or refrain from acting by overcoming that person’s free will and results in inequity. The statute identifies four factors courts must consider in determining whether undue influence occurred:
- Vulnerability of the victim: Incapacity, illness, disability, injury, age, education, impaired cognition, emotional distress, isolation, or dependency that affects the person’s ability to make independent decisions
- Apparent authority of the influencer: Fiduciary or confidential relationship, family relationship, professional relationship, or any other relationship that creates a power differential between the influencer and the decedent
- Actions and tactics of the influencer: Controlling necessary information, use of affection, intimidation, coercion, or threats, excessive monitoring of the decedent, isolation from family and friends, and direct or indirect use of financial control
- Equity of the result: The economic consequences of the transfer, including the appropriateness of the transaction in light of the length and character of the relationship and the needs of the parties
California’s Statutory Presumption of Undue Influence
California Probate Code Section 21380 creates a presumption of undue influence that arises in specific circumstances, shifting the burden of proof to the person who received the challenged gift. The presumption applies when a donative transfer is made to a person who is a transferor’s care custodian, a person who drafted the instrument, a person who is in a fiduciary relationship with the transferor, or a person who was in a confidential relationship with the transferor and who participated in procuring the transfer.
When the presumption applies, the recipient of the gift must prove, by clear and convincing evidence, that the transfer was not the product of undue influence. This reversal of the burden of proof is enormously significant in practice, because the contestant normally bears the burden of proving their case. The California Probate Code’s donative transfer provisions establish the specific conditions under which this presumption arises and the defenses available to rebut it.
The Evidence That Proves Undue Influence
Because undue influence occurs in private and the primary witness is unavailable, the evidentiary case is built primarily from circumstantial evidence that creates a compelling narrative when assembled together. The categories of evidence most important to a California undue influence case include:
- Medical records: Records from the period surrounding the challenged document’s execution that document the decedent’s cognitive status, physical condition, and susceptibility to outside influence. Neuropsychological evaluations, primary care records, and specialist notes are all potentially relevant
- Financial records: Evidence of unusual financial transactions, unexplained transfers of assets, and changes in the decedent’s financial arrangements that coincide with the person’s growing influence over the decedent’s affairs
- Isolation evidence: Documentation of the decedent’s reduced contact with family and friends during the period the influencer was present, including cancelled appointments, unreturned calls, and reports from people who attempted to contact the decedent and were prevented from doing so
- The attorney-client relationship: Evidence about who selected the estate planning attorney, who was present during the planning meetings, and whether the attorney had any prior relationship with the decedent independent of the influencer’s introduction
- Prior statements of intent: Testimony from family members, friends, and prior advisors about the decedent’s expressed intentions before the influencer’s involvement, creating a contrast with the final document
Building an Undue Influence Case With Experienced Counsel
The investigation required to build a viable undue influence case in California requires systematic collection of evidence across multiple categories, retention of expert witnesses including a forensic geriatrician or neuropsychologist who can testify to the decedent’s vulnerability, and a litigation strategy that develops the circumstantial case through discovery before trial.
Working with counsel experienced in proving undue influence in California will and trust cases means having a team that knows which evidence is most persuasive to LA County probate judges, how to deploy California’s statutory presumption when the facts support it, and how to build the comprehensive documentary record that turns a compelling narrative into a provable case.
