To 'Thread the Needle'

choi

Julie Hirschfeld Davis and Adam Goldman, Trump Demands an Investigation on Surveillance; Alleging campaign spy; Presidential intervention may force Showdown with Justice Fept. New York Times, May 21, 2018 (one of the two front-page top reports).

summary in the window of print: Speculation of a push to get rid of the deputy attorney general.

Quote:

(a) "President Trump on Sunday [May 20] demanded that the Justice Department investigated whether the department or the FBI 'infiltrated or surveiled' his campaign at the behest of the Obama administration

(b) "In response to president's [Twitter] post, the Justice Department asked its internal watchdog, the Office of the Inspector General, to expand its current inquiry into the surveillance of a former Trump campaign official to include the questions raised by the president [yesterday].

" 'If anyone did infiltrate or surveil participants in a presidential campaign, we need to know about it and take appropriate action,' Rod J Rosenstein, the deputy attorney general who is overseeing the Russian inquiry, said in a statement.

"By handing the question to the inspector general, Mr Rosenstein appeared to be trying to thread the needle, giving the president what he said he wanted without fully bowing to his demands.

My comment:
(a) I am clueless about the context of the demand. I am instead interested in "thread the needle:" what does it mean?
(b) thread the needle:
(i) "(idiomatic) to find harmony or strike a balance between conflicting forces, interests, etc. Normally used to indicate the difficulty of doing so; also, sarcastically, for a failed attempt"
https://en.wiktionary.org/wiki/thread_the_needle

Why?
(ii) "1 : to insert thread through the eye of a needle.
2: to pass something through a narrow space between two things  <The quarterback really threaded the needle with that pass between two defenders.>
3 : a children's game * * * "
Farlex Dictionary of Idioms. Farlex, Inc, 2015.
https://idioms.thefreedictionary.com/thread+the+needle