Model Rule 3.7: Lawyer as Witness
Rule 3.7 bars a lawyer from acting as advocate at a trial in which the lawyer is likely to be a necessary witness, unless an exception applies. The concern is that the trier of fact may confuse the lawyer's roles as fact witness and as zealous advocate, and the risk that the lawyer's own credibility and interest in the case will taint the fact-finding process. The rule is about the advocate's role at trial, not about whether the lawyer can represent the client at all pretrial stages.
When it applies
This comes up when a lawyer who drafted a contract, witnessed a signing, or has other firsthand knowledge relevant to a client's case is asked to also try that case; the MPRE tests whether students know the rule only bars acting as advocate at trial, not all representation, and whether an exception applies.
What the rule requires
- A lawyer shall not act as advocate at a trial in which the lawyer is likely to be a necessary witness.
- The prohibition is triggered by trial advocacy specifically - pretrial work, negotiation, and non-trial representation are not barred.
- "Likely to be a necessary witness" means the lawyer's testimony is needed and not merely cumulative or obtainable elsewhere.
- If the lawyer is disqualified from advocacy under this rule, other lawyers in the same firm may still act as advocate unless a conflict under Rule 1.7 or 1.9 also disqualifies the firm.
- The lawyer must assess this issue early, since discovering the problem mid-trial can be highly disruptive.
Exceptions
- The testimony relates to an uncontested issue.
- The testimony relates to the nature and value of legal services rendered in the case.
- Disqualification would work substantial hardship on the client, considering factors like the significance of the testimony and the difficulty of obtaining substitute counsel.
How the MPRE tests Model Rule 3.7
- Students often think the lawyer is barred from all representation of the client; the rule only bars acting as advocate at trial.
- Students forget the firm-imputation twist: co-counsel and firm colleagues are NOT automatically disqualified from serving as trial advocate just because one lawyer must withdraw as advocate under this rule.
- MPRE questions test whether testimony is truly "necessary" versus merely helpful or available from another source - only necessary testimony triggers the rule.
- Students confuse this with conflicts of interest rules (1.7, 1.9); 3.7 is about role confusion for the trier of fact (judge or jury), not about divided loyalty.
Example
A lawyer personally witnessed the signing of a disputed will and is the only person who can testify about the testator's mental state at that moment. If the case goes to trial, that lawyer cannot serve as trial advocate because the testimony is necessary and contested, but another lawyer in the same firm may try the case instead, since the disqualification does not automatically extend to law partners.
Related rules
On the MPRE
A plain-English summary of the ABA Model Rule, not the rule text. Your jurisdiction's version of the rule controls in practice.