neocon n.

also neoconservative; used in the modern sense by 1979:

My Republican vote [in the 1972 presidential election] produced little shock waves in the New York intellectual community. It didn't take long — a year or two — for the socialist writer Michael Harrington to come up with the term "neoconservative" to describe a renegade liberal like myself. To the chagrin of some of my friends, I decided to accept that term; there was no point calling myself a liberal when no one else did. [Irving Kristol, "Forty Good Years," The Public Interest, spring 2005]

The term is attested from by 1964 (neo-conservatism is by 1959; new conservative is from mid-1950s), originally often applied to Russell Kirk and his followers, who would be philosophically opposed to the later neocons. From neo- "new" + conservative (n.).