Where Do You Fight Over a Broken Promise to Make a Will?

When someone makes an oral agreement or a joint promise to leave their property to specific family members (like nieces and nephews) in their will, but later changes their mind and creates a new will or trust cutting those family members out, it triggers a major legal battle.

However, trying to solve that fight in the wrong courtroom can get your case thrown out immediately. In Estate of Mullins (1988) 206 Cal. App. 3d 924, a California appellate court clarified a crucial jurisdictional rule: you cannot use the probate court to impose a constructive trust based on an alleged breach of a contract to make a will.

The Big Mistake: Bringing a Contractual Claim to Probate Court

Before he died, Kieram Mullins and his wife May orally agreed that whichever spouse survived would leave their estate divided equally among both sides of the family. After Kieram passed away, May changed her mind, executed a new will and trust, and left 90% of the estate to her own relatives while heavily cutting out Kieram’s niece, Mary Hawley.

Mary filed a petition directly in the probate court, asking the judge to impose a "constructive trust" on the estate assets to honor the original oral agreement made by her uncle and aunt.

The probate court dismissed the case, ruling it had no jurisdiction to hear the matter. Mary appealed, arguing that modern probate trust laws gave the court broad powers to fix the issue. The Second District Court of Appeal affirmed the dismissal.

What Estate of Mullins Established

1. Constructive Trusts Are Outside Probate Jurisdiction: An action to enforce an oral agreement to make a particular testamentary disposition (a will contract) is legally enforceable, but the appropriate remedy is imposing a constructive trust in a general civil action.

   
   

2. Internal Affairs vs. Adverse Claims: Under California Trust Law (and Probate Code § 17000 et seq.), the probate court has broad power over the internal affairs of a trust (such as modifying administrative terms, replacing trustees, or handling financial management). But a claim that fights against the trust's distribution scheme based on an outside contract is an adverse claim against the estate, not an internal trust affair.

   
   

3. The Proper Forum: If a claimant is suing as a creditor or contract-holder claiming entitlement to property adversely to the named beneficiaries and the estate, they must file a regular civil action in the superior court, separate from the probate proceedings.

   
   

Key Takeaways for Estate and Trust Litigation

• Choose the Right Courtroom: If you are trying to enforce a promise to make a will or establish a constructive trust based on an outside agreement, filing a petition in the probate department will result in a dismissal for lack of subject matter jurisdiction.

  
  

• The Distinction Matters: The probate court manages administration and internal trust governance; civil courts handle equity claims, breach of contract, and the imposition of constructive trusts against competing beneficiaries.