When the Arab world boycotted companies trading with Israel, the United States accused them of breaching international law and attempting blackmail. But now, in a clear case of double standards, Washington is attempting to act in the same way against foreign firms doing business in Cuba.

President Bill Clinton's six-month suspension of some lawsuits under the Helms-Burton Act only postpones part of the problem. Foreign allies are already outraged by another section of the act that has come into force, barring leading international executives from visiting the US because of their involvement with companies active in Havana.

Despite the temporary delay in implementation, US subsidiaries of foreign firms will still be under the shadow of the act's provision making them liable for use by their parent company of Cuban property which may have been seized from US citizens nearly 40 years ago. Nor will the delay necessarily be enough to stop the European Union from retaliating by demanding visas from visiting US executives. But there is also a wider principle at stake. If Washington succeeds in exercising extra-territorial jurisdiction over foreign dealings with Cuba, in flagrant breach of international law and trading rules, then it will try to use the same tactic more widely.