He was one of the Three Princes, who Sisavang Vatthana appointed to form a coalition government between the rightists and Pathet Lao but it collapsed, and the Laotian Civil War began.
Souvanna Phouma announced that, with the holding of elections, the Royal Lao Government had fulfilled the political obligations it had assumed at Geneva, and the International Control Commission (ICC) adjourned sine die.
Prince Souphanouvong (July 13, 1909 — January 9, 1995) was, along with his half-brother Prince Souvanna Phouma and Prince Boun Oum of Champasak, one of the “Three Princes” who represented respectively the communist (pro-Vietnam), neutralist, and royalist political factions in Laos.
Fearing violence in Vientiane, the premier, Prince Somsanith Vongkotrattana, resigned, and the King named Souvanna Phouma prime minister.