This common-candidate scheme is an adaptation of the "guest candidate" recruitment in the pre-martial-law 2-party system
under which either the Nacionalista Party or the Liberal Party drafted extremely popular politicians to run as its presidential candidate, as in the case of the switch of then Defense Secretary Ramon Magsaysay from LP to NP as "guest candidate.
The Youth Parliament Pakistan has its own 2-Party system
, the Leader of the House and the Leader of the Opposition, a Youth Cabinet, a Shadow Cabinet and Parliamentary Committees.
BRITAIN'S 2-PARTY SYSTEM
TURNED ON ITS HEAD (The Daily Yomiuri as translated from The Yomiuri Shimbun's editorial published May 9)