In the 1960s, many people under the age of 21 were in the u. s. army fighting in a war in vietnam. however, several states did not allow people to vote in elections until they reached age 21. how was this situation addressed? a) the supreme court ordered states to change their laws b) the president signed a law requiring that all 18 year olds vote c) an amendment to lower the voting age was added to the u. s. constitution d) a new law was passed requiring members of the military be at least 21 years of age