[David O. McKay]
... In his letter, Elder Christiansen also states that two Temple Presidents have recently inquired regarding permitting couples to be married civilly before traveling from their home to the Temple within a few days to have the sealing solemnized in the Temple. We decided to send a letter to Presidents of Temples informing them that the First Presidency must be consulted in regard to any proposed civil marriage of couples desiring to go to the Temple to be sealed.
[David O. McKay diary, June 14, 1966, in Anderson, Devery; The Development of LDS Temple Worship, 1846-2000: A Documentary History, http://amzn.to/TempleWorship]