Put the kibosh on our parliament adopting US medical programme (6)
I believe the answer is:
derail
'put' is the definition.
Although both the answer and definition are verbs in their base form, I can't see how one could define the other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for derail that I've seen before include "Cause to run off the tracks" , "get off the line" , "Cause to come off the tracks" , "stop things going smoothly" , "come off the line" .)