In May 1975, shortly after the fall of Saigon and the Khmer Rouge conquest of Cambodia, Cambodians seized the American merchant ship "Mayaguez" in international waters, sparking what became known as the Mayaguez incident. Ford dispatched Marines to rescue the crew, but the Marines landed on the wrong island and met unexpectedly stiff resistance just as, unknown to the U.S., the "Mayaguez" sailors were being released. In the operation, two military transport helicopters carrying the Marines for the assault operation were shot down, and 41 U.S. servicemen were killed and 50 wounded while approximately 60 Khmer Rouge soldiers were killed. Despite American losses, the rescue operation proved to be a boon to Ford's poll numbers; Senator Barry Goldwater declared that the operation "shows we've still got balls in this country." Some historians have argued that the Ford administration felt the need to respond forcefully to the incident because it was construed as a Soviet plot. But work by Andrew Gawthorpe, published in 2009, based on an analysis of the administration's internal discussions, shows that Ford's national security team understood that the seizure of the vessel was a local, and perhaps even accidental, provocation by an immature Khmer government. Nevertheless, they felt the need to respond forcefully to discourage further provocations by other Communist countries in Asia.