On August 9, Captain Kong Le led the Second Paratroop Battalion of the Royal Lao Army in a virtually bloodless coup d'état that changed the history of modern Laos. In taking over Vientiane, the paratroopers had unwittingly chosen a moment when the entire cabinet was in Louangphrabang conferring with the king. They informed their compatriots and the outside world by broadcasting their communiqués on the radio. In a rally at the city football stadium on August 11, Kong Le expanded on his goals: end the fighting in Laos, stem corruption, and establish a policy of peace and neutrality. Recalling the experience of the first coalition when the country was temporarily at peace, Kong Le asked for the nomination of Souvanna Phouma as prime minister.
On August 11, General Ouan Ratikoun, as the cabinet's envoy, arrived in Vientiane from Louangphrabang. After negotiations with Kong Le and Souvanna Phouma as president of the National Assembly, Ouan returned to Louangphrabang with a document in which the coup leaders requested the cabinet to return. They agreed to withdraw their forces to specified points in the city and stipulated that these steps would lead to negotiations on the government's future. Two days later, however, when Ouan returned alone, it became evident that the cabinet was reluctant to return to Vientiane. Once this news spread, demonstrators gathered outside the Presidency of the Council of Ministers demanding Somsanith's immediate resignation; they next marched on the National Assembly, where Souvanna Phouma met them and, startled by their vehemence, attempted to moderate their demands. Inside, the forty-one deputies present voted unanimously to censure the Somsanith government. On August 14, a delegation of the assembly carried the news of this vote to Louangphrabang and asked the king to name Souvanna Phouma to form a new government. Fearing violence in Vientiane, Somsanith resigned, and the king named Souvanna Phouma prime minister. The new government was invested by thirty-four deputies on August 16. The next day, Kong Le declared his coup d'état over and vacated the Presidency of the Council of Ministers.
General Phoumi, opposed to the new Laotian government, enlisted the support of the commanders of four of Laos's five military regions. He also began immediately broadcasting propaganda denouncing Kong Le as a communist and on August 15 proclaimed the establishment of a Counter Coup d'État Committee. He appealed to all military personnel to rally behind him, guaranteed their salaries, and proclaimed his intention to liberate Vientiane from communist hands. Forces loyal to Phoumi seized Pakxan.
Souvanna Phouma, wanting to avoid civil war, with Phoumi's concurrence convoked the National Assembly in Louangphrabang on August 29, 1960. A new government with Souvanna Phouma as prime minister and Phoumi as deputy prime minister and minister of interior was sworn in on August 31. Phoumi announced the dissolution of his Counter Coup d'État Committee. This might have defused the crisis, but the same day, Kong Le made a radiobroadcast protesting the presence of Phoumi in the cabinet. Souvanna Phouma convinced him to change his mind, which he did "for the sake of peace and reconciliation" on September 1. Phoumi returned to Savannakhét and waited.
On September 10, Prince Boun Oum, speaking from Savannakhét in the name of the new Revolutionary Committee, announced that the constitution had been abolished, and he and Phoumi were assuming power. In mid-September, two companies of Kong Le's paratroopers routed the two battalions of Phoumi's advance guard from their position at Pakxan and installed a defensive line on the north bank of the Nam Kading. Phoumi made no move to organize his paratroop drop on Vientiane, in spite of the considerable means at his disposal.
On the evening of September 21, Sarit, military dictator and prime minister of Thailand, made a speech in which he hinted at Thai armed intervention in Laos. American officials in Bangkok believed that inadequate support for Phoumi might lead Sarit to intervene unilaterally in Laos because he had already imposed a blockade on Vientiane. The US embassy in Vientiane worked out a compromise with Souvanna Phouma, in which the prime minister would not object to direct United States military aid to Phoumi as long as this aid was not used against his government.
Kong Le's reputation as a giant slayer had by now spread from the capital to the far corners of the kingdom. On September 28, when he dropped a handful of paratroopers near Xam Nua in order to explain the situation to the 1,500-person garrison that in principle was loyal to Souvanna Phouma, rumors that the garrison's officers, some of whom had been in contact with Phoumi, might be cashiered created a panic. The garrison abandoned the town to the Pathet Lao, who were accompanied by their North Vietnamese advisers from Group 959. The withdrawing column surrendered its arms to the Pathet Lao near Muang Peun on October 2.
The Pathet Lao now claimed to be supporting Souvanna Phouma. The coup and Phoumi's resistance with foreign assistance, which the United States and Thailand had difficulty camouflaging, allowed the Pathet Lao to proclaim themselves nationalists. Many Laotians came to see the Pathet Lao as acting to defend the country against American and Thai backed aggression. Even in Vientiane, there was growing resentment of the Thai blockade, which caused a shortage of consumer goods and rising prices. Foreseeing an opening for the Pathet Lao to negotiate with the new government, Radio Hanoi and Radio Beijing broadcast support for Souvanna Phouma.
Phoumi began his attack on Vientiane on December 13. From his command post near the airport, Kong Le had positioned his men at key points on the outskirts, intending merely to fight a delaying action to allow the safe evacuation to the north of his men and their equipment. The regional command post of the Pathet Lao, situated at Na Khang, sixty kilometers north of the capital, disposed of three guerrilla groups but did not take part in the battle of Vientiane. A massive display of firepower by Phoumi's troops resulted in the deaths of 400 to 500 civilians in the town, mostly Vietnamese residents, and the wounding of another 1,000 to 1,500 civilians. Kong Le's troops only lost seventeen killed. Phoumi's armor rolled into town on December 16.
Kong Le retreated slowly northward toward Louangphrabang, while Soviet aircraft parachuted badly needed supplies--rice, salt, sugar, blankets, light arms, ammunition, and radios. With new recruits, his ranks had swelled from 800 to 1,200 men. On December 23, at Phôn Hông, about sixty kilometers north of the capital, Kong Le was visited by Kaysone, who had come to settle the details of distribution of Soviet aid and coordination of Neutralist and Pathet Lao troops in future operations. On January 1, 1961, Kong Le's troops took control of the Plain of Jars and Khang Khay after skirmishing with some of the 9,000 Phoumist troops and an equal number of Hmong guerrillas in the vicinity and recovered large quantities of supplies. The following day, the Neutralists occupied Xiangkhoang, and United States advisers and Phoumist troops were evacuated from the Muang Phônsavan airfield.
The Soviet airlift, which continued despite United States protests to Moscow, transformed the Plain of Jars into a vast armed camp, fully resupplying Kong Le. For the first time, the Pathet Lao were equipped with heavy weapons allowing them to play a major role in their military alliance with Kong Le's troops in support of Souvanna Phouma's government. There was, moreover, another and more important factor: the commitment of significant numbers of North Vietnamese troops to the fighting. Kong Le requested four battalions of North Vietnamese troops on January 7, 1961. The Neutralists were now aligned with the Pathet Lao and their North Vietnamese allies.