Clue: About employer who makes things go down in America? (6)
Answer: CAUSER
Explanation: Definition: who makes things go
A charade of CA (*circa*, 'about') plus USER ('employer'). I am a little puzzled by 'down in America' (apart from the thematic 'down'). Is it Brendan's point that causer rather than cause is a Americanism? I have not been able to dig up any support for this.