Nothing exceptionally surprising. The US used its clout to pressure the EU to become more pro-GM. And, knowing the Catholic church is a strong influence in developing countries, they lobbied hard in that sector, as well.

Link

In response to moves by France to ban a Monsanto GM corn variety in late 2007, the ambassador, Craig Stapleton, a friend and business partner of former US president George Bush, asked Washington to penalise the EU and particularly countries which did not support the use of GM crops. ... Because many Catholic bishops in developing countries have been vehemently opposed to the controversial crops, the US applied particular pressure to the pope's advisers. ... "Opportunities exist to press the issue with the Vatican, and in turn to influence a wide segment of the population in Europe and the developing world," says another [cable].

The language in these documents show how conservatives plan for the long game, not for immediate results.

"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.

"The list should be measured rather than vicious and must be sustainable over the long term, since we should not expect an early victory. Moving to retaliation will make clear that the current path has real costs to EU interests and could help strengthen European pro-biotech voices," said Stapleton, who with Bush co-owned the Dallas/Fort Worth-based Texas Rangers baseball team in the 1990s.

[Emphasis mine - min]

But, recently, they somehow lost the support of the Vatican.

But in a setback, the US embassy found that its closest ally on GM, Cardinal Renato Martino, head of the powerful Pontifical Council for Justice and Peace and the man who mostly represents the pope at the United Nations, had withdrawn his support for the US.

"A Martino deputy told us recently that the cardinal had co-operated with embassy Vatican on biotech over the past two years in part to compensate for his vocal disapproval of the Iraq war and its aftermath - to keep relations with the USG [US government] smooth. According to our source, Martino no longer feels the need to take this approach," says the cable.

1) I find it dismaying that the reason the Vatican changed its message to support GM crops was cause they felt bad about criticizing the US government for invading Iraq, which they damn well ought to have criticized them for if they believe any of the (New Testament) religious stuff they preach. Either there's more to the story than we know or the Vatican really is taking Catholic guilt too far.

2) What did the US government do to annoy them enough that they decided they weren't playing anymore?