This short news article from NewsOK.com is cited here in full:
A law requiring people to be U.S. citizens before they can be licensed to give lie detector tests is unconstitutional, Attorney General Drew Edmondson said in an opinion issued Friday.
Under the Polygraph Examiners Act, an individual applying for licensing must be a citizen of the United States.
Using existing case law, Edmondson and Assistant Attorney General Joann Stevenson concluded that the law is unconstitutional under the Equal Protection Clause of the Fourteenth Amendment to the U.S. Constitution.
Polygraph examiners do not occupy important nonelective positions where they directly affect public policy, Stevenson said in the opinion.
Other states have come to similar conclusions when considering citizenship requirements for notary publics, according to the opinion.