A key element in the rapid expansion of green building in the USA has been the leadership role of national, state and local governments in promoting sustainability through their own capital works progammes. Public agencies are collectively the major US builders and also control much university, school and health expenditure. The Federal General Services Administration has endorsed and mandated the US Green Building Council’s LEED standard, as has the Defence Department. States including California and Washington and many cities have adopted LEED silver (equivalent to about 4 Stars) for new projects and renovations. The recent US Mayors conference adopted a detailed new policy. Chicago has a comprehensive programme starting its own buildings, promoting green roofs, providing assistance for commercial, private and community developments and issuing expedited permits for green buildings. A number of local governments now offer additional financial assistance, height and density for sustainable projects.