In yesterday’s central committee meeting of the opposition New Politics Alliance for Democracy (NPAD), party members approved an initiative for nomination reforms, which embattled Chairman Moon Jae-in pinned his position on. With the committee decision, Moon passed a first confidence vote. But another one is supposed to be coming up. The party’s internal schisms are anything but fixed.Ahn Cheol-soo didn’t attend the meeting after his demands for the postponement of the meeting and the withdrawal of a public poll for the confidence vote were not met. The nonmainstream faction of the party walked out in protest of Moon’s decision not to allow a secret ballot vote. That translates into a demonstration of political distrust of Moon.
I'm struggling to understand the role and meaning of 'pin' in the bold line.
I guess the sentence means Chariman Moon can prepare for the battle(obviously the national election), maintaining or keeping his position as a chairman on.
As to my personal syntax analysis,
An initiative embattled Chairman Moon (being) pinned his position on.
S V O
'Chairman Moon is pinned his position on '
can be paraphrased as
'His position pins on Chairman Moon.'
I searched the meaning of pin in Merriam dictionary.
1 a : to fasten, join, or secure with a pin b : to hold fast or immobile c : to present (a young woman) with a fraternity pin as a pledge of affection
2 a : fasten b : to assign the blame or responsibility for c : to define or determine clearly or precisely —usually used with down
3 a : to make (a chess opponent's piece) unable to move without exposing the king to check or a valuable piece to capture b of a wrestler : to secure a fall over (an opponent)
It is a transitive verb, so I don't understand how 'pin' works in the sentence in the perspective of both gramar and meaning in context.
Thank you in advance!