where does 'gate' stem from (scandals)

[prydey]

i'm just curious why all the scandals end up with 'gate' tacked on the end. seems to have only started recently. first i can remember is some 'iguanagate' thing, but now even the v8's have used it with the splitter thing (splittergate). sounds pretty retarded if you ask me. just wondering where its come from and what it means.