38 U.S.C. § 1102

(a) No compensation shall be paid to the surviving spouse of a veteran under this chapter unless such surviving spouse was married to such veteran— (1) before the expiration of fifteen years after the termination of the period of service in which the injury or disease causing the death of the veteran was incurred or aggravated; or (2) for one year or more; or (3) for any period of time if a child was born of the marriage, or was born to them before the marriage. (b) Subsection (a) shall not be applicable to any surviving spouse who, with respect to date of marriage, could have qualified as a surviving spouse for death compensation under any law administered by the Secretary in effect on December 31, 1957 .