THE United States has threatened to expel Swaziland from a key trade pact for developing countries if the Swazi king fails to enact new labour legislation. The US embassy in Mbabane said the US will drop Swaziland from its Generalised System of Preferences list unless the government passes a new industrial relations bill ahead of the International Labour Organisation annual conference in June. Under the GSP, developing countries can export a range of products, including sugar, textiles and timber, to the United States at reduced tariffs.