Swing killed a lot in US? All of the above (4)
I believe the answer is:
slew
'swing' is the definition.
(both can mean to slide out of control)
I don't understand the rest of the clue.
(Other definitions for slew that I've seen before include "a great number in Chicago" , "making sharp turn" , "Butchered" , "Move obliquely or sideways, often losing control" , "Suddenly turn" .)