In 18 years of consulting to hundreds of law departments, I have yet to see a formal statement of rules to determine whether a law firm is in conflict with the company. The common coin enjoins law suits brought against the company retaining a firm. Beyond that, I suspect that constitutional-like statements of principles, if even those, come into play. For example, is every adversarial proceeding a law suit? What about filing a bankruptcy claim against a subsidiary? How recently must a law firm have represented a company to conflict it out? What if the conflict-creating partner has left the firm recently? Can the firm represent a potential litigant and then withdraw if a summons and complaint is filed?
I am no expert in the area of conflicts. [See my post of May 1, 2005 (5) on Freivogel and conflicts.] I suspect that conflicts are almost always situationally-defined and law departments operate on contingency principles. For that reason, when it comes to determining conflict situations, they are not civil law but common law.