In the case of Bernal v. Fainter, 467 U.S. 216 (1984), the Supreme Court of the United States ruled that the Equal Protection Clause prohibited the state of Texas from barring noncitizens from applying for commission as a notary public.

The Supreme Court decided that since the requirements of being a notary are essentially ministerial (that is, without judgement or discretion, either the person fits the statutory requirement to have a document authenticated or they do not), and the only real requirement of a notary was to follow the law, being a notary does not have any special character of citizenship that would require one to necessarily be a citizen. This is unlike, say, being a police officer, where a locality may require police officers to be citizens because they act on behalf of the state and have considerable discretion in how the law is enforced.

The Supreme Court struck down the Texas law that required a notary to be a citizen. The court also noted that notary commissions are issued by the Texas Secretary of State, who, ironically enough, is not required to be a citizen.

• Findlaw.Com Text of decision (http://caselaw.lp.findlaw.com/scripts/getcase.pl?navby=case&court=us&vol=467&page=216)
• List of United States Supreme Court cases