Mediation after ABA Opinion 518:  What are a lawyer's responsibilities? 

The American Bar Association would not publish a major ethics opinion on mediation unless something in our field had drifted badly off course.

Well, something has.

And something had to be done about it. So we should welcome ABA Formal Opinion 518 (Oct. 25, 2025).

The problem

For years, the mediation field has been flooded -- and I use that word deliberately -- with retired judges and aged-out partners who enter mediation without ever mastering it as a discipline. Very few become true students of the game. Once in a blue moon, someone unschooled becomes a genuinely excellent mediator -- but that's about as common as Athena springing fully formed from the brow of Zeus.

And many users of mediation assume that if someone is on the panel of a big ADR company, quality is assured. But that assumption is misplaced. Mediators insist -- fiercely -- on being independent contractors, not employees. Because of that, ADR providers are legally prohibited from controlling, supervising, or directing the means and methods their panel mediators use.

So many newly minted mediators are not adequately trained, and they are not quality-controlled. The burden falls on us -- the legal profession -- to set real standards.

That is the backdrop for Opinion 518.

What Opinion 518 does

What Opinion 518 does, at its core, is strip away the habits into which mediators fall when they have not mastered the craft. It tells us clearly:

• A mediator may not do anything "dishonest, fraudulent, deceptive, or misleading." (Section III, Para. 2.)

• A mediator may not "make misleading statements about the strength or weakness of a party's case." (Section III, Para. 8.)

• And -- this is the heart of the opinion -- a mediator should not say "that a proposed settlement is in a party's best interest."  (Section II, Para. 3.)

That last prohibition has the mediation world asking the right question: Does this prohibit the mediator's proposal? 

The mediator's proposal is a last-resort tool to settle a case when negotiations stall. The mediator proposes a  set of terms, and each side responds privately, "yes" or "no." If both say "yes," the case settles; if either says "no," the mediator announces "no deal," and the declining party never learns the other side's response. The design protects parties from being asked to bid against themselves when they are willing to compromise, but their counterparts are not.

The ethics of mediator's proposals

First, we need to say something that ought to be obvious: mediators are required to be neutral. What does that mean? Neutrality is not a matter of attitude or intention or absence of bias. We all have bias -- much of it unconscious, much of it implicit. A neutral process is one which protects parties from having mediators' biases steer the outcome and gives parties the opportunity they deserve to determine where the case will settle. Neutrality thus exists to protect party self-determination.

Viewed through this lens, let's ask what makes a mediator's proposal ethical under Opinion 518.

To be neutral, a proposal must be equally good for both sides. A mediator cannot issue a mediator's proposal the mediator believes is better for one side than the other.

So the question becomes: Can any mediator's proposal satisfy neutrality?

The only mediator's proposal that is theoretically neutral is the midpoint between the last offer and last demand. The midpoint seems to show equal respect for each side's position. But the moment parties suspect the midpoint may become the proposal, the entire mediation becomes a slow-motion attempt to tilt the midpoint in their favor. It incentivizes stinginess, distorts movement, and poisons genuine negotiation.

What's left? The non-midpoint proposal the mediator selects on his own, or pulls from his ear.

But here is the unavoidable truth: Once a mediator chooses a non-midpoint number, neutrality is gone. The disadvantaged party sees it instantly: "He's closer to their number. He bought their story. He's not neutral."

There is an additional ethical problem, one Opinion 518 does not emphasize but the Model Standards do. Under the ABA/AAA/ACR Model Standards of Conduct for Mediators, Standard I(B) says a mediator shall not undermine party self-determination for reasons such as higher settlement rates, egos, or increased fees.

An unvetted, pulled-from-the-ear number does exactly that. It is the mediator and not the parties who decides where the case should settle. The mediator's choice may stem from a sense that one side is more malleable, more flexible, more eager to get out of there. And when a mediator drops a number that is less favorable to one side for those reasons, it is precisely what Standard I(B) forbids.

Does a non-midpoint mediator's proposal imply a best-interest judgment?

Turning back to Opinion 518's central prohibition, we must ask the most critical question: does a pulled-from-the-ear, non-midpoint proposal inevitably imply that the mediator believes this number is in a party's best interest?

For a mediator to believe the proposal is "equally good for each side," the mediator must first believe the proposal is "good" for each side. If the mediator believes the number is the best a party can get in the negotiation, and better than the alternative of going to trial -- in other words, "good" -- that is a best-interest judgment.

And Opinion 518 now forbids that.

It then becomes the responsibility of lawyers to make sure mediators do not subject them to proposals with numbers selected by the mediator. Not to do so would risk placing lawyers in violation of their own ethical obligations.

The delegation problem

The deeper issue lies not with mediators at all, but with lawyers' own ethical limits.

Model Rule 1.1 requires lawyers to provide competent representation.

Model Rule 5.3 then draws boundaries around delegation: Lawyers may delegate responsibility only to non-lawyers who are "employed or retained by or associated with" the lawyer, and over whom the lawyer has "direct supervisory authority."

Although your mediator may hold a bar card, the mediator does not have an attorney-client relationship with anyone in the mediation. Therefore, for Rule 5.3 purposes, the mediator functions as a non-lawyer.

Is a mediator eligible under Rule 5.3 to be delegated lawyering tasks? No. The mediator is not "employed or retained by or associated with" you in the Rule 5.3 sense -- the mediator is jointly retained by you and your adversary. And the mediator is never under your "direct supervisory authority." The mediator is supervised as much by your adversary as by you.

These are the lines everyone forgets. And they are the lines too many mediators cross when lawyers allow mediators to pick the mediator's proposal number.

Compare ordinary delegation in a high-volume personal injury practice. Plaintiffs' lawyers routinely delegate substantial responsibility to paralegals. But imagine delegating to a paralegal who is half on the trial lawyer's payroll and half on the insurance company's payroll. No competent lawyer would tolerate that. Neither would any client. It's absurd.

By the same logic, how can any lawyer delegate to a mediator -- who owes as much obligation to your adversary as to you -- responsibility to determine the number at which the case should settle?

The hunger for control in the name of "getting it settled" pushes mediators into a role only counsel can ethically fulfill: determining the final settlement number. And too many lawyers, unfortunately, let it happen.

Opinion 518 restores guardrails that should never have been moved. It reminds us that lawyers cannot outsource their lawyering to mediators, and mediators cannot quietly assume powers no lawyer can ethically delegate.

Is the mediator's proposal dead?

Not at all. It means the unvetted mediator's proposal is dead.

The vetted mediator's proposal -- grounded in party self-determination rather than a mediator's attachment to settlement for settlement's sake -- is very much alive.

Here's how it works. When the moment feels right, the mediator -- or counsel -- may raise the idea of a proposal. If both sides are interested, the mediator does not pull anything from his ear. Instead, the mediator works with the lawyers to shape a proposal that they -- the lawyers -- would recommend to their own clients. The mediator's proposal becomes the subject of neutral, facilitated negotiation: "You want a mediator's proposal? OK, let's talk about what it should be. I want to make sure both lawyers are willing to recommend it before I issue it."

When the parties are close -- for example, frozen at 55 and 65 after hours of good-faith bargaining -- it may be acceptable to say, "60 kind of suggests itself. What do you think?" Sometimes the mediator speaks with the lawyers separately, sometimes together. There may be several rounds of back-and-forth before the lawyers reach a number each can recommend. It lands where it lands.

What matters is this: the lawyers, not the mediator, determine whether the proposal is in their client's best interest before it is made. And when each lawyer is prepared to recommend a proposal, the likelihood of getting two "yes" answers is about 99 and 77/100 percent. The mediator has not chosen a number. The mediator has not implied whether the proposal is in anybody's best interest. The mediator has preserved neutrality and honored self-determination.

Do mediators still add value?

For all of this talk about constraints on what mediators can do, mediators still add real value. The fact that mediators cannot replace counsel does not mean mediators cannot support counsel and benefit clients.

Within proper limits, evaluative input from mediators has a legitimate role. It's through the hard questions on the merits, the costs, the delay, and the mental wear and tear of conflict that only a mediator can raise without undermining advocacy. Those conversations help clients see their cases more clearly and help lawyers manage expectations without surrendering their role.

One last problem -- and why lawyers alone can solve it

While Opinion 518 makes the ethical obligations of mediators clear, it has no enforcement mechanism of its own. And mediation confidentiality may bar introduction of errant mediator conduct in a disciplinary proceeding. So the constraints become real only when lawyers insist they be so.

Lawyers must recognize when they are at risk of ceding too much authority to mediators. And lawyers must ensure they perform the work the Rules of Professional Conduct reserve for them alone.

In the end, Opinion 518 does not constrain good mediators. It empowers good lawyers. It restores the line between facilitating negotiation and practicing law. It keeps mediators on one side of that line and lawyers on the other. And it ensures that clients receive the distinct, ethical services they are entitled to from each professional -- preserving the value of mediation itself.