(a) Eligibility A person who is not a licensee of the State Bar of California but who is an attorney in good standing of and eligible to practice before the bar of any United States court or the highest court in any state, territory, or insular possession of the United States, and who has been retained to appear in a particular cause pending in a court of this state, may in the discretion of such court be permitted upon written application to appear as counsel pro hac vice, provided that an active