The transatlantic transgenic trade war has begun. Since 1998, when the European Union (EU) stopped approving new transgenic food crops for sale, US farmers have been seething. And last week, their government finally moved to open EU markets to genetically modified (GM) food, mounting a legal challenge to Europe's moratorium.

While few in US government or industry are happy about the EU's position, even fewer believe there is much to gain from taking the case to the World Trade Organization (WTO) at this late stage. The State Department, in particular, is opposed to anything that would strain already fractious US–European relations still further. Crop biotechnology companies would also have preferred a diplomatic route.

There are various motivations for the WTO suit (see page 369). But in the event, the action may have as much to do with domestic US politics as anything else. Senator Chuck Grassley (Republican, Iowa) had warned that he would speak out if the challenge were not filed soon. As chair of the Senate Committee on Finance, responsible for pushing through the administration's tax cuts, Grassley is not someone with whom President George W. Bush wanted to fall out.

The problem is that the suit stands to do little good. The EU moratorium had appeared likely to end later this year anyway, as soon as strict rules requiring GM produce to be labelled are finalized. The danger now is that EU member states might respond by continuing their moratorium for another year or so, until the suit is resolved. Even if the WTO rules in favour of the United States, an aggrieved Europe might defy the ruling and pay any retaliatory import duties that the United States would then impose.

Such tit-for-tat measures are in no one's interest, however. Although it might be seen as capitulation, the sensible response would be for the EU to swallow its pride and lift its embargo, as soon as its labelling rules are in place. So far, there is no scientific evidence suggesting that GM crops pose a special risk to human health or the environment. Countries may still reject any GM crop or product that is subsequently shown to pose a demonstrable hazard. And once labelling is in place, consumers who distrust the technology can simply reject GM food in the marketplace.