Is there a term for when a politician sends an anonymous idea to see whether the public is receptive?
In any democratic country, I guess, sometimes politicians want to see whether an idea is acceptable in the prevailing public opinion, but at the same time they don't want to reveal their position on an issue until they are sure of the outcome.
Something like this happens in case of controversial issues where politicians want their action placed in a positive perspective and where to express an unpopular idea may be problematic.
So, my question is, is there a term for when a politician sends an anonymous idea to see whether the public is receptive?
A trial balloon is “an idea, suggestion, or prospective action, product, etc. offered to an audience or group in order to test whether it generates acceptance or interest”. A trial balloon can be generated sort of secretly or deniably via a planned leak. A related term is stalking horse, “A candidate put forward instead of any of several potentially successful candidates in order to initiate a leadership debate, gauge feelings, divide opposition etc.”
Test the water(s)
- The politician tried to test the waters with his latest manoeuvre.
This idiom may not meet all your constraints, but comes close.
To try to ascertain probable reaction or response before making a proposal, selling a product, etc
The phrase I've heard most often for this is kite-flying:-
the act of trying to find out what people's opinion about something new will be by informally spreading news of it
He could run it up the flagpole and see who salutes.
The linked article mentions "trial balloon" as a more serious alternative.
The closest I can think of is leaking :
2) Informal To disclose without authorization or official sanction: leaked classified information to a reporter.
I had not heard of kite-flying but that sounds perfect. It seems to be more of a British/Irish/Australian (Commonwealth?) term but according to this page an American equivalent might be
Raising the flag to see who salutes