A few days ago I reported that the New York State Bar Association was considering expelling Rudy Giuliani from its membership. See here. However, the NYSBA is just not a regulatory agency so expulsion from the association would not affect Giuliani's ability to practice law in the state.
Since then, however, at least two groups of lawyers have filed complaints about Giuliani before the appropriate regulatory agency in New York, which could lead to discipline. Obviously, all the complaints can do is advocate for the agency to take action. The agency will decide whether to conduct an investigation and, then, what to do given the results of the investigation. Like any other disciplinary complaint, it could be dismissed, or it could start a process that could result in disbarment. But a lot has to happen before it gets to that point.
The 18 page document (plus appendices) essentially argues that Giuliani should be disciplined for violating the New York versions of Model Rules 8.4, 4.1, and 3.1, related to the duties of honesty, trustworthiness, and the duty not to pursue frivolous litigation. The complaint argues that Giuliani engaged in dishonest conduct by knowingly lying about the results of the election and pursuing a court challenge with no support. It concludes that “A lawyer who lies to the public and abuses the court system to undermine democracy and the rule of law is not fit to practice law.”
The other complaint, which makes very similar arguments, was brought on behalf of Michael Miller, a past President of both the New York State Bar Association and the New York County Lawyers Association and was signed by dozens of prominent lawyers and academics. You can read that one here.