expression, godan verb (-u)
lose a seat (in an election)
Used specifically for losing an elected parliamentary seat. The verb 失う (to lose) is transitive, and the object 議席 (parliamentary seat) is marked with を.
与党は今回の選挙で多くの議席を失った。
The ruling party lost many seats in this election.
彼はスキャンダルで議席
He ended up losing his seat due to a scandal.