On July 31, 1951, a formal pact between the right-wing Batllist fraction of the Colorados – the Colorado and Batllist Union (Unión Colorada y Batllista – UCB) – and the Herrerist Movement (Movimiento Herrerista) of the Blancos called for a plebiscite on constitutional reform.
The plebiscite the following December 16 drew less than half of the 1.1 million voters to the polls, but the collegial system was approved by a small margin.
[1] As the culmination of an effort to reestablish the colegiado and the plural executive power, a fourth constitution was promulgated on January 25, 1952.
The chief executive could nominate only four of the nine ministers from his own party faction; the General Assembly selected the other five through separate votes in both chambers.
[1] This nine-member colegiado, which headed the executive branch from 1954 to 1967, was ineffective because the president lacked control over the ministers and because the majority was seldom united.