What Are Non-Waivable and Nonconsentable Conflicts?

A conflict of interest is nonconsentable when a client’s written waiver cannot cure it. ABA Model Rule 1.7(b) identifies three such situations: the lawyer cannot reasonably believe they will still provide competent and diligent representation, outside law prohibits the representation, or one client the lawyer represents is asserting a claim against another client the lawyer represents in the same proceeding before a tribunal.¹ If any one of those three applies, informed consent is not an option.

The Three Categories That Can’t Be Waived

Most conflicts can be waived. Rule 1.7(b) allows a lawyer to proceed despite a conflict if four conditions all line up: the lawyer reasonably believes competent and diligent representation is possible, outside law does not prohibit the representation, the clients are not asserting claims against each other in the same proceeding, and each affected client gives informed consent confirmed in writing.¹

The first three conditions do the work this article is about. Each describes a situation where the problem is structural rather than informational. The client’s willingness to accept the risk is not the issue; the representation itself cannot be made adequate. Written consent in that setting is meaningless.

When the Lawyer Can’t Reasonably Believe the Work Will Be Competent

Rule 1.7(b)(1) is the broadest nonconsentable category. It asks whether the lawyer can reasonably conclude that they will provide competent and diligent representation to every affected client despite the conflict. If the honest answer is no, a waiver cannot rescue the engagement.¹

The standard is objective. It does not turn on the lawyer’s self-assessment but on what a disinterested, reasonable lawyer would conclude from the facts. The ABA Comments explain that consentability depends on whether the clients’ interests will be “adequately protected” if they are allowed to consent, not on how willing the clients are to take the risk.²

Personal Interest Conflicts

Comment 10 to Rule 1.7 warns that a lawyer’s own interests “should not be permitted to have an adverse effect on representation.” It flags situations like the lawyer being in discussions about possible employment with an opposing party’s firm, or referring clients to a business in which the lawyer holds an undisclosed financial interest.² Picture a lawyer with a significant ownership stake in a corporation who is then asked to sue that same corporation. The incentive to protect the investment pulls directly against the obligation to fight hard for the client. A waiver signed with full knowledge of the investment does not change that pull.

Value Conflicts and Deeply Held Beliefs

The same logic reaches lawyers whose personal beliefs would compromise zealous advocacy. If an attorney finds the client’s objectives fundamentally abhorrent, the risk that the attorney will pull punches — consciously or not — can be too great for the objective standard to tolerate. The concern is not ordinary discomfort but situations where the lawyer’s capacity to function as a genuine advocate is damaged at the core.

When Outside Law Forbids the Representation

Rule 1.7(b)(2) covers conflicts where a statute, regulation, or binding court decision bars the representation regardless of what the lawyer and client agree. The restriction originates outside the ethics rules themselves.¹

Comment 16 gives three concrete examples. Some states prohibit a single lawyer from representing more than one defendant in a capital case, even with the defendants’ consent. Federal criminal statutes restrict certain representations by former government lawyers despite the consent of the former client. And case law in some states limits whether a governmental body, such as a municipality, can even consent to a conflict at all.²

Capital Cases

The capital case restriction exists because the stakes leave no room for divided loyalty. When the death penalty is on the table, the risk that one defendant’s defense will be sacrificed to benefit another, through plea negotiations, testimony strategy, or how the lawyer allocates time, is treated as incurable. The judgment is not left to the defendants, because the consequence of getting it wrong cannot be undone.

Former Government Lawyers

ABA Model Rule 1.11 governs conflicts involving lawyers who previously worked for the government. A lawyer who personally and substantially participated in a matter while in government service cannot later represent a private client in the same matter unless the government agency gives informed consent in writing.³ “Matter” is defined broadly to include judicial proceedings, investigations, contracts, charges, and other situations involving specific parties.

Rule 1.11 is more forgiving than many other conflict provisions in one respect: even when the individual lawyer is disqualified, the lawyer’s new firm can still handle the matter if that lawyer is screened from all participation, receives no fee from the case, and the government agency is promptly notified in writing.³

When Two Clients Oppose Each Other in the Same Proceeding

Rule 1.7(b)(3) draws the sharpest line of the three. A lawyer cannot represent one client while asserting a claim against another client the same lawyer represents in the same litigation or other proceeding before a tribunal.¹ The adversarial system assumes each side has a dedicated advocate, and a lawyer sitting on both sides cannot deliver that for either client.

The Comments identify the reason as the “institutional interest in vigorous development of each client’s position.”² One lawyer cannot argue a claim is valid while also mounting its defense. They would have to cross-examine their own client, or use one party’s confidential information to help the other. These contradictions are built in. Goodwill from the parties cannot remove them.

What Counts as a Tribunal

The prohibition applies to proceedings before any “tribunal,” which under the Model Rules includes courts, administrative agencies, and other bodies acting in an adjudicative capacity. Mediation is not a proceeding before a tribunal under this definition, so paragraph (b)(3) does not technically bar one lawyer from representing adverse parties in a mediation. Comment 17 cautions, however, that such a representation may still fall under paragraph (b)(1), the reasonable belief standard, if the lawyer cannot realistically serve both clients well.²

Co-Plaintiffs and Co-Defendants Are Different

Paragraph (b)(3) only bars representation of parties directly adverse to each other. Representing co-plaintiffs or co-defendants nominally on the same side is a general conflict under paragraph (a)(2), which can potentially be waived with informed consent. The Comments add a caution, though, that the potential for conflict among criminal co-defendants is “so grave that ordinarily a lawyer should decline to represent more than one codefendant.”² Consent being theoretically available does not make it wise.

How the Conflict Spreads to the Rest of the Firm

A nonconsentable conflict rarely stays with one lawyer. Under ABA Model Rule 1.10, when lawyers practice together in a firm, none of them can take on a representation that any one of them would be individually barred from handling.⁴ If one partner has a nonconsentable conflict with a potential client, every lawyer in the firm is disqualified from the matter.

Two narrow exceptions soften that result. If the conflict stems purely from the disqualified lawyer’s personal interest, such as a family relationship or a financial stake, and does not create a significant risk of limiting the other lawyers’ representation, the rest of the firm can proceed. If the conflict arises from a lawyer’s prior association with a different firm, screening that lawyer from the matter and giving written notice to the affected former client can allow the current firm to take the case.⁴ For former government lawyers, Rule 1.11’s own screening provisions apply instead of the general imputation rule.

What Happens If a Lawyer Takes the Case Anyway

Proceeding with a nonconsentable conflict carries consequences on several fronts. The first is mandatory withdrawal. ABA Model Rule 1.16(a)(1) requires a lawyer to withdraw from any representation that would result in a violation of the ethics rules or other law.⁵ Withdrawal is not optional. If the lawyer does not step aside, the court can order disqualification, often well into the litigation.

Beyond withdrawal, state bar discipline can follow, ranging from a reprimand to suspension or disbarment depending on severity and whether the lawyer acted knowingly. A client harmed by the conflicted representation can bring a malpractice claim, which proceeds on the standard negligence framework of duty, breach, causation, and damages. Fee forfeiture is often the practical sting: courts may order the lawyer to return some or all of the fees earned during the conflicted representation, on the view that the client did not receive what was paid for.

For the client, a mid-case disqualification means hiring new counsel who must get up to speed on the entire file. That translates into delay, extra expense, and sometimes a weakened position if the earlier lawyer’s divided loyalties affected strategy or missed deadlines. The nonconsentability rules exist to head off exactly that harm, and clients who sense one of these three categories in their representation are better off raising it early than discovering the problem after judgment.

1
American Bar Association. Model Rules of Professional Conduct – Rule 1.7: Conflict of Interest: Current Clients
2
American Bar Association. Rule 1.7 Conflict of Interest: Current Clients – Comment
3
American Bar Association. Rule 1.11: Special Conflicts of Interest for Former and Current Government Officers and Employees
4
American Bar Association. Rule 1.10: Imputation of Conflicts of Interest: General Rule
5
American Bar Association. Rule 1.16: Declining or Terminating Representation