通す: maintaining a position and passing thread through a hole
Read the reported maintenance of one's own position until the end, comparing it with passing thread through a small hole.
Identify what was maintained until the end
通す (とおす) means to pass through or carry through. The position example centers on the actual act of maintaining one's own position until the end.
Read 自分の主張 with 最後まで to identify what was maintained and how far that maintenance continued. Compare the thread example while keeping a maintained claim separate from a proven truth or unanimous agreement.
Compare maintaining a claim with passing thread
「彼は最後まで自分の主張を通した。」 (He maintained his position until the end.) What he maintained until the end was his own position. 通した reports the past action; it does not establish that the claim was proved true or that everyone agreed.
「細い穴に糸を通した。」 (I passed the thread through the small hole.) The thread was actually passed through a small hole. 糸 identifies the object passed, and 細い穴 identifies its route. Use this to compare the objects of the two actions.
Preserve the scope of the maintained position
With thread, 通す concerns passing an object through an opening. With a position, it concerns maintaining the person's own claim until the end. The named object distinguishes the physical passage from the maintained stance.
The position sentence establishes that he maintained his own position until the end. It supplies no reaction from others or collective agreement, so keep the answer centered on the position maintained.
What was maintained until the end in the position example?
Show the answer and why
The person's own position was maintained. The sentence reports that action; it does not prove the claim true or establish that everyone agreed.