Earlier intervention in Laos in 1961 was also considered at one stage.In April 1961 elements of the US 7th Fleet did deploy to the Gulf of Siam,and a Marine Helicopter Squadron Group deployed to Udorn.
http://www.history.navy.mil/seairland/chap2.htm
By the end of April most of the Seventh fleet was deployed off the Indochinese Peninsula preparing to initiate operations into Laos. The force consisted of Coral Sea (CVA 43) and Midway (CVA 41) carrier battle groups, antisubmarine support carrier Kearsarge (CVS 33), one helicopter carrier, three groups of amphibious ships, two submarines, and three Marine battalion landing teams. At the same time, shorebased air patrol squadrons and another three Marine battalion landing teams stood ready in Okinawa and the Philippines to support the afloat force. Although the administration of President John F. Kennedy already had decided against American intervention to rescue the Laotian government, Communist forces halted their advance and agreed to negotiations. The contending Laotian factions concluded a cease-fire on 8 May 1961, but it lasted only a year.
Fleet training exercises also served to highlight American strength and purpose in Southeast Asia. Exercise Pony Express, conducted on the northern coast of Borneo by 60 ships and 26,000 personnel from SEATO member states between late April and early May 1961, prominently displayed U.S. naval power and allied military solidarity. Throughout this period, the Navy took other steps to reaffirm the U.S. commitment to friendly governments.
However proposals that combat troops be sent into Laos were rejected:
http://www.fas.org/irp/nsa/spartans/chapter3.pdf
To counter the communist threat, the Pentagon developed OPLAN X-61, a plan for U.S.troops to enter Laos, as well as a SEATO version,Field Forces Plan 5-61. The U.S. Seventh Fleet sent additional carriers to the South China Sea,while a U.S. Marine battalion was readied to land in Thailand. Exactly how many U.S. troops would be committed remained sketchy - planners favored numbers anywhere from 60,000 to 140,000 men, though U.S. Secretary of State Dean Rusk opted for 10,000 troops in an enclave around Vientiane...
... However, the proposed intervention never materialized. The most likely explanation is that President Kennedy simply did not want to fight a war in Laos. He and his advisors had developed a low regard for the military capability of Phoumi's forces. The Royal Laotian Army,along with its ethnic Meo and Hmong units, had outnumbered the Pathet Lao and Kong Le forces,yet the latter had gained the upper hand by April.An advisor to Kennedy had derided RLA as"clearly inferior to a battalion of conscientious objectors from World War I." Also, the U.S.Army's chief of staff and U.S. Marine Corps' commandant were skeptical of supporting a full-blown military intervention, citing logistics and terrain problems as prohibitive factors.Instead, in early May 1961 the two Laotian factions sat down to negotiate another coalition arrangement. It has been suggested by some offi-ial U.S. histories that the impetus for the meetings by the Laotians was the possibility of U.S. military intervention. At the time, there was an ongoing Southeast Asia Treaty Organization exercise known as Pony Express, which was practicing an insertion of military forces in a notional country to meet an external assault. The combination of the announced possibility of U.S. inter-vention and the existence of SEATO forces prac-ticing such a contingency may have impressed the Laotian factions.
Photo from:
http://www.combatreform2.com
US 7th Fleet,South China Sea 1961
