The general assembly shall provide by law for the nomination of candidates; for a uniform system of permanent registration of voters; for the exemption from such registration of persons in the active service of the nation and their families absent from the state because of such service, and, in time of war, members of the Merchant Marine; for absentee and shut in voting; for the time, manner and place of conducting elections; for the prevention of abuse, corruption and fraud in voting; and may define by law residence for voting purposes, but no person shall acquire such residence merely by being stationed or assigned in this state in the active service of the United States.