Another troubling subplot has emerged from the trove of diplomatic cables that journalists have been poring through. This time it’s the United States’ less-than-heroic role in last year’s Copenhagen climate change summit, which was widely viewed as a failure for the toothless Copenhagen Accord that resulted. Since this is the last day of the United Nations Climate Change Conference in Cancun, it seems a good time to walk through the way promising climate negotiations get deliberately derailed.

1. Collude with China.

In May of 2009, Senator John Kerry met with China’s Deputy Prime Minister Li Keqiang in Beijing, reports Der Spiegel. Kerry told Keqiang that Washington understood China’s “resistance to accepting mandatory targets at the United Nations Climate Conference” coming up in Copenhagen. A cable sent from the U.S. embassy in Beijing reported that Kerry outlined “a new basis for ‘major cooperation’ between the United States and China on climate change.” A secret alliance between the two countries had been suspected by many; the cables appear to verify it.

2. Make offers poor nations can’t refuse.

Small island states like the Maldives have the most to lose from climate change (it’s why they make poster children for the cause). They also tend to be rather poor. The cables reveal that the U.S. made an offer the Maldives couldn’t refuse: millions of dollars of aid, apparently in exchange for compliance with the U.S.’s wishes at Copenhagen. U.S. climate negotiator Jonathan Pershing told the Maldives’ ambassador to name a number. “Other nations would then come to realize that there are advantages to be gained by compliance,”went the thinking in a U.S. memo spotted by Der Spiegel.

3. If they do refuse, punish them.