From my understanding a discursive essay is whereby you take a view point on the trueness of a statement, but should discuss for and against the statement.
However, if a question is very straight cut, answer is untrue, or true...how can you argue against its trueness, or for it? I could be misunderstanding what a discursive essay should do - and I get that on a lot of legal points it is possible to argue for and against an idea, however the question I have is not really about the substance of law.
I.e 'The main difference between ketchup and mayonnaise, is ketchup is red and mayonnaise is not. Discuss'.
Silly example but I hope you see my point...
...or just paranoid?