Wills vs. Trusts: Why Courts Apply Different Mental Capacity Standards — and Why It Matters

Published: March 2026 | Author: Riefkohl Law
Category: Estate Litigation, Trust Law, Undue Influence

Most people assume that if someone has the mental capacity to sign a will, they have the capacity to sign any estate planning document. A recent New York appellate decision says that assumption is wrong — and the distinction can determine the outcome of an entire estate dispute.

In Matter of Baird (Cardelli), decided March 18, 2026, the New York Supreme Court Appellate Division, Second Department, drew a sharp line between the mental capacity required to execute a will and the mental capacity required to execute a trust. The standards are fundamentally different, and the court’s analysis provides essential guidance for anyone involved in estate planning, trust administration, or fiduciary litigation.

The Case

The facts involved a decedent who had executed both a 2019 will and a linked revocable trust. The decedent’s daughter and granddaughter challenged both instruments, alleging undue influence by individuals who had a confidential relationship with the decedent. The Surrogate’s Court dismissed the claims on summary judgment, finding insufficient evidence to proceed.

The Appellate Division reversed. In doing so, it clarified the distinct legal standards governing challenges to wills versus challenges to trusts — a distinction the lower court had improperly conflated.

Testamentary Capacity: The Standard for Wills

For wills, New York applies the “testamentary capacity” standard. This is a deliberately low bar. The proponent of the will bears the burden of proving that the testator, at the exact moment of signing, understood three things: that they were making a will; the general nature and extent of their property (a macro-level awareness of what they owned, not a detailed accounting); and the “natural objects of their bounty” — meaning they knew who their close family members were and who would naturally be expected to inherit.

Testamentary capacity is measured at a single point in time. A person who is confused in the morning but lucid in the afternoon has testamentary capacity during that afternoon window. The standard deliberately favors validity — the law presumes that people have the right to dispose of their property as they see fit, and the threshold for exercising that right is intentionally minimal.

In practice, will contests based on lack of testamentary capacity are difficult to win. Attorneys-in-fact who supervise the signing, self-proving affidavits, and testimony from the drafting attorney and attesting witnesses typically establish the baseline.Contractual Capacity: The Standard for Trusts

The Appellate Division held that trust validity is governed by a different and significantly more demanding standard: contractual capacity. To possess contractual capacity, an individual must have the cognitive ability to fully understand the specific nature of the transaction they are entering into at the time the document is executed.

This goes well beyond the three-factor testamentary test. A trust is a complex legal instrument that involves the creation of a fiduciary relationship, the transfer of legal title to a trustee, the retention or disposition of beneficial interests, and detailed provisions governing distributions, powers of appointment, tax elections, and successor trustees. Understanding “the nature of the transaction” means understanding these mechanics and their legal and financial implications.

The practical consequence is clear: a person may have sufficient mental acuity to understand that they are signing a will and know who their children are, but lack the cognitive ability to understand the legal architecture of a revocable trust with multiple beneficiary classes, distribution standards, and tax planning provisions.

Undue Influence: The Appellate Division Revived the Claims

Beyond the capacity distinction, the Appellate Division found that the objectants had raised triable issues of fact regarding undue influence. The court determined that evidence of a confidential relationship — combined with questions about the circumstances surrounding the execution of the documents — was sufficient to survive summary judgment.

This aspect of the ruling is significant for practitioners. It underscores the high evidentiary burden required to dismiss undue influence claims before trial, especially when familial or fiduciary relationships suggest potential influence. Summary judgment is a powerful tool for proponents of estate plans, but this case demonstrates that courts will not grant it when genuine factual disputes exist about the dynamics surrounding document execution.Why This Distinction Matters for Estate Planning

The divergence between testamentary and contractual capacity has immediate practical implications for both estate planning and estate litigation.

For estate planners drafting documents, the higher standard for trusts means that capacity assessments must be more rigorous when a client is executing a trust than when they are signing a simple will. If there is any question about a client’s cognitive state, the drafting attorney should consider obtaining a contemporaneous medical evaluation, documenting the client’s understanding of the trust’s provisions in detail, and ensuring that the execution ceremony is witnessed and potentially recorded. These precautions are particularly important for elderly clients or clients with progressive cognitive conditions.

For litigators challenging estate plans, the distinction opens a strategic pathway. A trust may be vulnerable to a capacity challenge even when the accompanying will is not. Because the standards are different, a court could theoretically uphold a will while invalidating the trust — splitting the estate plan and potentially producing distribution outcomes that neither the decedent nor the challenger anticipated.

For families concerned about a loved one’s cognitive state, this ruling clarifies that the question is not simply “can they sign documents?” The question is whether they can understand the specific nature of each document they are signing. A person signing a complex trust instrument must comprehend more than a person signing a straightforward will.

The Takeaway

Matter of Baird (Cardelli) provides a definitive statement from New York’s appellate courts on a question that matters enormously in estate planning and fiduciary litigation. The mental capacity to execute a will and the mental capacity to execute a trust are not the same. Practitioners who conflate them — whether in drafting, litigation, or administration — do so at their client’s peril.

If you are planning your estate, advising a client, or considering a challenge to an estate plan, understanding this distinction is not optional. It is foundational.

Need help with estate planning, trust administration, or fiduciary litigation? Contact Riefkohl Law — serving clients in Puerto Rico and across the United States.

riefkohllaw.com | hans.riefkohl@riefkohllaw.com

This article is provided for educational and informational purposes only. It should not be construed as legal advice. Consult with a qualified attorney regarding your specific situation.