text: The National voting age was 21 for both the election years you ask about.  Some states allowed younger voting before it became national law to allow the 18 year old to vote, just as some states had allowed the Womens vote before it became National Law in 1920.  The first National Election that 18 year olds were able to vote in was in 1972 when Richard Nixon won a landslide victory over George McGovern.