At the federal or Commonwealth level, progress has moved much more slowly. Between 1996 and 2007, the Liberal Government under Prime Minister John Howard made constant attempts to prevent states and territories from recognising same-sex couples, and halted efforts to amend nearly 60 pieces of legislation which recognise opposite sex couples explicitly. In 2004, same-sex marriage became officially prohibited at the federal level after the Marriage Act 1961 was amended by the Marriage Legislation Amendment Bill.