Every male citizen of this state who is a citizen of the United States, and every male resident of foreign birth, who, before the ratification of this Constitution, shall have legally declared his intention to become a citizen of the United States, twenty-one years old or upwards, not laboring under any of the disabilities named in this article, and possessing the qualifications required by it, shall be an elector, and shall be entitled to vote at any election by the people; provided, that all foreigners who have legally declared their intention to become citizens of the United States, shall, if they fail to become citizens thereof at the time they are entitled to become such, cease to have the right to vote until they become such citizens.