As the guerrillas were being pressured by enemy troops pushing to within ten kilometers of their main bases, the aerial campaign was planned to cause a pullback by the pressing communists.
As the first well-targeted aerial campaign in Laos, Operation Raindance's 65 strikes per day gained such great results that it was extended indefinitely.
When France withdrew most of its military in conformity with the treaty, the United States filled the vacuum with purportedly civilian paramilitary instructors.
[3] After the failure and defeat of Operation Pigfat, the communists had overrun the Plain of Jars to within ten kilometers of the guerrillas' main base at Long Chieng.
[4] Hmong General Vang Pao not only suffered the reverses of his failed offensive, and the loss of a forward airfield at Muang Soui; his defensive position was soon further weakened by Vietnamese communist attacks.
Now, faced with the possibility of a final guerrilla defeat, American Ambassador William H. Sullivan and Lao Prime Minister Souvanna Phouma loosened the restrictive rules of engagement inherent in the Operation Barrel Roll bombing campaign.
[6] For the first time, the CIA, the Embassy air attaché and USAF planners jointly planned a strike package of 345 targets, complete with supporting documentation on aerial photographs.
Sixty sorties per day would be allocated to direction by Raven Forward Air Controllers; twenty would strike the enemy lines of communication, Route 7.
By the close of 18 March, so many secondary explosions and petroleum fires were reported that Seventh Air Force decided to continue the campaign "as long as resources are available, lucrative targets exist, and weather permits".
Bomb damage assessments reported included 486 secondary explosions of munitions, 570 buildings and 28 bunkers destroyed, 288 fires, six gun positions, and a 105mm howitzer.
Forces Armées Neutralistes operating in the hills around Muang Soui were poised on the Lima Site 19 mountaintop position southwest of it by 30 March.
Bomb damage assessment reported amounted to 1,512 storage caches struck, resulting in 765 secondary explosions from munitions and petroleum products.
On 21 April, a Bullpup missile detonated a cavern storing fuel and munitions; the near-simultaneous eruption of a village about a kilometer away proved they were linked via tunnel.
With the 103rd Bataillon Parachutiste (103rd Parachute Battalion) added to the irregulars, the combined force moved down from their hill position to Phonsavan on 29 April.
In the ruins of the town smashed by artillery and air strikes, they found two BTR-40 Armored Cars, 18 other vehicles, 12 37mm antiaircraft guns, and a 75mm howitzer, which they destroyed.
Continuing through town two kilometers to the northwest, on the north side of Route 4 they uncovered a cave complex crammed with pre-positioned communist supplies.
Still another contained over a mile of supplies within it; as the cache was too big to ruin, local Buddhist monks were convinced to lay a curse upon it so the superstitious Pathet Lao would not reclaim the goods.