Can a lawyer oppose another lawyer's client when that other lawyer is the first lawyer's own client or former client?
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This page answers the general question as of 1981. Ezel answers yours: whether it's allowed on your facts, under the current Illinois Rules of Professional Conduct, with citations.
Plain-English summary
Lawyer A had represented Lawyer B in a matter that was now concluded. A asked whether he and B could represent opposing clients against each other and, if so, whether the clients' informed consent was needed; and whether the answer would change if A's representation of B were still ongoing.
The committee answered yes to the first question (no consent required) and no to the second. It framed the issue under Canon 5, Rule 5-101(a) (a lawyer's own financial, business, property, or personal interests), and Rules 5-105(a) and (b) (declining or continuing employment that would adversely affect independent professional judgment), and noted Canon 9's appearance-of-impropriety admonition has no operative rule covering the question.
The committee reasoned that a lawyer's function is adversarial by nature and that lawyers routinely deal with, and develop social relationships with, other lawyers; none of that should bear on independent professional judgment. It said that where a lawyer's relationship with opposing counsel is so close that he sincerely feels his judgment would or might be affected, he should remove himself, but that this is a matter of personal judgment no rule can capture. The fact that A had represented B in a now-concluded matter does not, by itself, require refusal, withdrawal, or even disclosure; if the situation is dictated by personal conscience, disclosure would not change it.
Currency note
This opinion was issued in 1981, under the former Illinois Code of Professional Responsibility and before Illinois adopted the 2010 Rules of Professional Conduct. The ISBA Board of Governors affirmed the opinion in July 2010 as generally consistent with the 2010 Rules (Rules 1.7 and 1.9), while cautioning that the specific standards referenced may differ from the 2010 Rules. Subsequent rule amendments or later opinions may have changed the analysis. Treat this page as historical context, not current guidance. Verify against current rules before relying on any specific rule or requirement mentioned here.
Common questions
Q: Can a lawyer take a case against a client of a lawyer he once represented?
A: The opinion concluded yes, where that earlier representation of the other lawyer is concluded; the prior attorney-client relationship between the two lawyers does not, by itself, require refusal, withdrawal, or disclosure.
Q: Is the clients' informed consent required?
A: Per the opinion, no consent is required in the concluded-representation scenario, because the past relationship between the lawyers does not per se affect independent professional judgment.
Q: What if the lawyer still represents the other lawyer?
A: The committee answered no to that scenario; the lawyers may not take the opposing representations while the representation of the other lawyer is ongoing.
Q: When should a lawyer step aside because of a close relationship with opposing counsel?
A: The opinion says that if the lawyer sincerely feels his independent professional judgment would or might be affected by the relationship, he should remove himself, but it treats that as a matter of personal judgment no rule can dictate.
Background and rules framework
The opinion applied Illinois Supreme Court Canon 5, Rule 5-101(a) (a lawyer's own interests), and Rules 5-105(a) and (b) (employment adversely affecting independent judgment), and noted Canon 9 (appearance of impropriety) supplies no operative rule here. The Board's 2010 affirmation maps the analysis to current Illinois Rules of Professional Conduct 1.7 (concurrent conflicts) and 1.9 (former clients), corresponding to ABA Model Rules 1.7 and 1.9.
Citations and references
Rules of Professional Conduct:
- Illinois Supreme Court Canon 5; Rule 5-101(a); Rules 5-105(a), (b); Canon 9 (applied in the opinion)
- Illinois RPC 1.7, 1.9 (2010 equivalents per the Board's affirmation)
- MR 1.7 (concurrent conflicts; personal-interest conflicts); MR 1.9 (former clients)
See also
- ISBA Ethics Op. 691: Firm Conflict Against a Former Client
- ISBA Ethics Op. 790: Representing a Party Against a Former Client
- ISBA Ethics Op. 85-11: Client Against the Spouse of a Former Client
Source
- Landing page: https://www.isba.org/ethics/opinions/724
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