A lawyer who was formerly a government employee cannot represent a client if what condition exists?

The requirement that a lawyer who was formerly a government employee cannot represent a client if they personally and substantially participated in the matter while in government is rooted in the principle of avoiding conflicts of interest and maintaining the integrity of the legal profession. This rule is designed to prevent situations where confidential government information, or the potential for bias or favoritism, could unfairly benefit the lawyer's client in the private sector.

When a lawyer has personally and substantially participated in a matter during their time as a government employee, they have likely been exposed to sensitive information or insights that could give their new client an unfair advantage. This could undermine the public's trust in the legal system and the government itself, as it may appear that private interests are being favored at the expense of fairness or public duty.

In contrast, if the matter is unrelated to their previous government work, or if the lawyer did not participate personally in it, there would typically be no conflict of interest, and the lawyer might proceed with representation. Additionally, obtaining written consent from the government agency does not apply if the lawyer was substantially involved in the matter, as consent cannot override the duty to avoid conflicts stemming from substantial participation.