When may there be a conflict of interest with a former client?

Hypo 1: Bob represented Sam in a patent infringement case regarding Sam's revolutionary battery technology. The case settled two years ago. Now, TechCorp approaches Bob to represent them in a new patent infringement case against Sam, involving the same battery technology. Result: This is a clear conflict under Rule 1.9(a). The new matter is substantially related to Bob's previous representation of Sam, and TechCorp's interests are materially adverse to Sam's. Bob cannot represent TechCorp unless Sam gives informed consent, confirmed in writing. Given the sensitivity of patent cases and the directly competing interests, it's unlikely that Sam would consent or that Bob could ethically proceed even with consent.

Hypo 2: Bob represented Sam in a divorce case five years ago. Now, Sam's ex-spouse wants to hire Bob for a contract dispute with their business partner. The contract dispute is unrelated to any marital assets or issues from the divorce. Result: This scenario likely does not create a conflict under Rule 1.9(a). While Sam is a former client, the new matter (a business contract dispute) is not the same as or substantially related to the previous matter (the divorce). Unless Bob learned confidential information during the divorce that's relevant to the current contract dispute, he could likely represent Sam's ex-spouse without Sam's consent. However, Bob should still consider any potential issues and, out of an abundance of caution, might choose to inform Sam and seek consent.

Hypo 3: Bob represented SmallTech in negotiating a licensing agreement with BigCorp two years ago. Now, BigCorp wants to hire Bob to sue SmallTech for breach of that same licensing agreement. Result: This presents a clear conflict under Rule 1.9(a). The new matter (the breach of contract lawsuit) is the same as or substantially related to the previous matter (negotiating the contract), and BigCorp's interests are materially adverse to SmallTech's. Bob cannot represent BigCorp unless SmallTech gives informed consent, confirmed in writing. Given that Bob likely has confidential information about SmallTech's position and strategies regarding this agreement, it would be very difficult for Bob to ethically proceed, even with consent.

Hypo 4: Bob represented Sam in a personal injury case resulting from a car accident last year. Now, Sam's neighbor wants to hire Bob for a property boundary dispute against Sam. Result: This scenario likely does not create a conflict under Rule 1.9(a). The new matter (a property dispute) is not the same as or substantially related to the previous matter (a personal injury case from a car accident). The interests are technically adverse, but the matters are not related. Unless Bob learned confidential information during the personal injury case that's somehow relevant to the property dispute, he could potentially represent the neighbor.

Hypo 5: Bob represented EcoCorp in an environmental compliance audit three years ago. Now, a group of residents wants to hire Bob to sue EcoCorp for environmental damages, based on issues that were not part of Bob's audit but occurred during the same time period. Result: This situation presents a potential conflict under Rule 1.9(a). While the new matter (environmental damage lawsuit) is not exactly the same as the previous matter (compliance audit), it could be considered substantially related if Bob gained relevant confidential information during the audit. The residents' interests are clearly materially adverse to EcoCorp's. Bob would need to carefully assess whether his knowledge from the audit could be relevant to the new case. If there's any significant relation, Bob would need EcoCorp's informed consent, confirmed in writing, to represent the residents. Given the sensitivity and potential overlap of environmental issues, it might be ethically safest for Bob to decline this representation.