DR 9-101 Avoiding Even the Appearance of Impropriety. 
  
  - A lawyer shall not accept private employment in a matter upon the merits of which he has
    acted in a judicial capacity.
- A lawyer shall not accept private employment in a matter in which he had substantial
    responsibility while he was a public employee.
- A lawyer shall not state or imply that he is able to influence improperly or upon
    irrelevant grounds any tribunal, legislative body, or public official.