You have an environmental law practice and are currently representing a client in county A that is defending against a complaint by the state environmental protection agency alleging that the client’s use of a certain pesticide poses a threat to the local groundwater.
Recently, you have been contacted by a prospective client in rural county B who wants you to file a suit against a neighboring farmer to prevent the farmer from using a similar pesticide. If you take the case, you would have to argue that the pesticide is toxic and will contaminate the local groundwater.
Although the pesticides are not identical, they are very similar and a favorable ruling in one case might have an adverse effect on the other.
Can you agree to represent the individual from county B?
In 1993, the ABA Standing Committee on Ethics and Professional Responsibility issued Formal Opinion 93-377 Positional Conflicts. In this opinion, the committee examined the ethical issues that are implicated when a lawyer represents one client in a matter in which the client’s interests with respect to a substantive legal issue are directly adverse to a position the firm is advocating on behalf of another client on the same or similar issue. As the committee noted, positional conflicts raise a number of ethical issues:
…[A]rguing a position on behalf of one client that is adverse to a position that the lawyer, or her firm, is arguing on behalf of another current client raises a number of concerns. For example, if both cases are being argued in the same court, will the impact of the lawyer’s advocacy be diluted in the eyes of the judge(s)? Will the first decision rendered be persuasive (or even binding) precedent with respect to the other case, thus impairing the lawyer’s effectiveness–and, if so, can the lawyer (or firm) avoid favoring one client over the other in the “race” to be first? And will one or the other of the clients become concerned that the law firm it has employed may have divided loyalties?
The committee looked to Model Rule 1.7 Conflict of Interest: General Rule as it existed in 1993 prior to the ABA Ethics 2000 Commission’s (E2K) revisions to the Model Rules for guidance. The committee also referred to paragraph  of the Comment to Rule 1.7 as it existed in 1993 that stated as follows:
A lawyer may represent parties having antagonistic positions on a legal question that has arisen in different cases, unless representation of either client would be adversely affected. Thus, it is ordinarily not improper to assert such positions in cases pending in different trial courts, but it may be improper to do so in cases pending at the same time in an appellate court.
The committee took issue with this comment, noting that representing two clients in different trial courts while advocating opposing sides of the same issue could manifest as conflicts of interest under Rule 1.7 just as they could if both matters were pending in the same appellate court. A decision in one trial court could influence the outcome of the second matter in the other trial court, and a decision in an appellate court would most likely have an adverse effect on a matter pending at the trial court.
With regard to matters pending in the same jurisdiction, the committee concluded:
The Committee is therefore of the opinion that if the two matters are being litigated in the same jurisdiction, and there is a substantial risk that the law firm’s representation of one client will create a legal precedent, even if not binding, which is likely materially to undercut the legal position being urged on behalf of the other client, the lawyer should either refuse to accept the second representation or (if otherwise permissible) withdraw from the first, unless both clients consent after full disclosure of the potential ramifications of the lawyer continuing to handle both matters.
For matters that are not being litigated in the same jurisdiction the committee suggested several questions a lawyer might consider, including the relative importance of the positional conflict issue and the likelihood that it may affect the outcome of one or both of the cases, the extent to which a decision in one case might influence the decision in the other and the extent to which the lawyer might “pull his punches” in one case so as to minimize any adverse effects on the client in the other case.
In 2002, the ABA E2K reviewed the comments to Rule 1.7 and deleted paragraph , replacing it with the current paragraph  that states as follows:
Ordinarily a lawyer may take inconsistent legal positions in different tribunals at different times on behalf of different clients. The mere fact that advocating a legal position on behalf of one client might create precedent adverse to the interests of a client represented by the lawyer in an unrelated matter does not create a conflict of interest. A conflict of interest exists, however, if there is a significant risk that a lawyer’s action on behalf of one client will materially limit the lawyer’s effectiveness in representing another client in a different case;… Factors relevant in determining whether the clients need to be advised of the risk include: where the cases are pending, whether the issue is substantive or procedural, the temporal relationship between the matters, the significance of the issue to the immediate and long-term interests of the clients involved and the clients’ reasonable expectations in retaining the lawyer. If there is significant risk of material limitation, then absent informed consent of the affected clients, the lawyer must refuse one of the representations or withdraw from one or both matters.
The E2K official Reporter’s explanation of changes memo re Model Rule 1.7 is located here. The Restatement of the Law Governing Lawyers has also weighed in on this issue. See, §128 cmt. f (2000) that states that a lawyer “ordinarily may take inconsistent legal positions in different courts at different times,” but that “a conflict is presented when there is a substantial risk that a lawyer’s action in Case A will materially and adversely affect another client in Case B.”
State bar opinions
There have been some state bar ethics opinions that have considered this issue applying a general conflicts of interest analysis. In some of these opinions, unique features of their state conflicts of interest rules also shape their analysis. See e.g., Maine Board of Overseers to the Bar Opinion 155 (1997) Arguing Different Sides of Same Legal Issue in Unrelated Cases.
…Although we conclude that an “issue conflict” standing alone is not a conflict within the meaning of Bar Rule 3.4(b), we note that counsel has an obligation to both clients under Rule 3.6(a)(1) to employ “reasonable care and skill” and to “employ the lawyer’s best judgment” in the representation of her clients. In light of this rule, an attorney must be mindful of the possibility that contemporaneously arguing opposite sides of the same issue before the same judge or panel of judges could impair her effectiveness on behalf of both clients, thereby arguably violating Rule 3.6(a)(1). It is not possible to define all the circumstances in which this rule might be implicated, since it will depend on the particular facts and circumstances.
Note that in 2009, the Maine Supreme Judicial Court adopted the Maine Rules of Professional Conduct. The Maine version of paragraph 24 of the Comment to Rule 1.7 is similar to the ABA version.
See also Oregon Opinion 2007-177 (2007) (A lawyer may not represent a client in a matter requiring him to contend for something that he must contend against on behalf of another client in another matter, if the outcome of one matter is highly likely to affect the outcome of the other.)
Oregon Rule 1.7(b) (3) specifically addresses the positional conflicts issue, stating:
b) Notwithstanding the existence of a current conflict of interest under paragraph (a), a lawyer may represent a client if:
… (3) the representation does not obligate the lawyer to contend for something on behalf of one client that the lawyer has a duty to oppose on behalf of another client;
See also District of Columbia Bar Opinion 265 (1996), a digest of which as it appears in the ABA/BNA Lawyers’ Manual on Professional Conduct states as follows:
A lawyer who regularly represents foster children and who is asked to serve as general counsel to an association of foster parents may not, unless all affected clients give informed consent, take inconsistent positions of law on behalf of the different clients if it is substantially likely that success on behalf of one client might affect the other client adversely.
For further information on positional conflicts, See Rotunda and Dzienkowski, Positional Conflicts § 1.7–6(o), The Lawyers’ Deskbook on Professional Responsibility (2016-17). See also Mallen, 2 Legal Malpractice § 17:5 Conflicting interests defined—Issue conflicts (2017 ed.), the discussion following the heading Positional Conflicts that appears at page 51:117 of the ABA/BNA Lawyers’ Manual on Professional Conduct and Richmond, Choosing Sides: Issue or Positional Conflicts of Interest, 51 Fla. L. Rev. 383 (1999)
As always, check the applicable rules of professional conduct, ethics opinions and case law of the jurisdiction. Your state or local bar association may also be able to help.