 Although "Afroyim" appeared to rule out any involuntary revocation of a person's citizenship, the government continued for the most part to pursue loss-of-citizenship cases when an American had acted in a way believed to imply an intent to give up citizenship—especially when an American had become a naturalized citizen of another country.In a 1980 case, however—"Vance v. Terrazas"—the Supreme Court ruled that intent to relinquish citizenship needed to be proved by itself, and not simply inferred from an individual's having voluntarily performed an action designated by Congress as being incompatible with an intent to keep one's citizenship.The concept of dual citizenship, which previously had been strongly opposed by the U.S. government, has become more accepted in the years since "Afroyim".