Mc ‧ Na ‧ ma ‧ ra, Robert S. /ˌmæknəˈmɑːrə $ ˈmæknəˌmærə ˈrɒbət $ ˈrɑːbərt/ BrE AmE
(1916–) a US politician who became Secretary of Defense in 1961, and who left his position 1968 because he and President ↑ Johnson did not agree about US policy in ↑ Vietnam .