Vietnam's march into its smaller, weaker neighbour in late 1978, with weapons supplied by the Soviet Union, looked to many observers like a classic annexation. The Vietnamese themselves did not attempt to defend their action as a ‘humanitarian intervention’, although they expected much of the world to approve their removal of the Pol Pot regime. This obsessively secretive Cambodian government had cut off its population from most contacts with the outside world since coming to power in April 1975. Over the nearly four years of Pol Pot's rule, news of the brutal agrarian regime he inflicted on Cambodia had seeped out via refugees who made their way to the Thai border. A Khmer-speaking US diplomat, Charles Twining, had spent months in these border camps interviewing refugees and cross-checking their stories of hunger and executions. Another Khmer speaker, Father François Ponchaud, had published his findings on Khmer Rouge brutality in Le Monde in February 1976, when he estimated that as many as 800,000 killings had occurred. The basic outlines of what was going on in Cambodia were thus becoming well known when Twining testified at hearings of the House International Relations Subcommittee in July 1977.