The initiative, which dates back to 2007, represents a response to moves by France to ban Monsanto's genetically-modified (GM) maize strain at that time.
"Country team Paris recommends that we calibrate a target retaliation list that causes some pain across the EU since this is a collective responsibility, but that also focuses in part on the worst culprits," wrote US Ambassador Craig Stapleton in a cable dated 14 December 2007.
"The list should be measured rather than vicious and must be sustainable over the long term, since we should not expect an early victory," he added.
The cable was drafted after France suspended marketing and growth on its territory of GM corn strain MON 810, a GM crop produced by US biotech giant Monsanto. The crop has EU-wide authorisation.
Stapleton stressed that together with France's attachment to the precautionary principle, the ban had set "a precedent with implications far beyond MON-810 BT corn cultivation".
The US ambassador called for a "retaliation list" to be drawn up, particularly since in his view France would play "a leading role" in the acceptance of agricultural biotechnology in Europe and in shaping the EU's approach to environmental regulation more generally.
US tandem with Spain
Another cable sent by the US embassy in Spain suggests that Washington and Madrid should build a close relationship and draw up a joint strategy to help boost the development of GM crops in Europe.
The cable, dated 19 May 2009, notes that Spanish Secretary of State for the Environment Josep Puxeu asked the US to "maintain pressure on Brussels to keep agricultural biotechnology an option for member states" and called on the US government to "work together with Spain in this endeavour".
Spain was the first EU country to grow GM corn and now cultivates some 75% of the EU's MON 810 crop.
Vatican under pressure
A cable from the US embassy in the Vatican, drafted in late 2009, suggested that Vatican officials remain "largely supportive" of GM crops as a means of feeding the hungry, but at the same time are unwilling to challenge bishops who disagree.
Many Catholic bishops in developing countries are vehemently opposed to the controversial crops, and the cable lamented that "the Vatican does not - at least not yet - feel that it is its duty to challenge them".
The US embassy, therefore, will continue to lobby the Vatican to speak up in favour of GMOs, in the hope that a louder voice in Rome will encourage individual Church leaders elsewhere to reconsider their critical views, the cable notes.