Deputy Leader of the Opposition in the Legislative Council 17 February 1993 – 30 November 1993; Leader of the Opposition from 30 November 1993 to 15 October 1996. He was also Shadow Minister for Transport from 17 February 1993 – 7 February 1994; for Education, Employment and Training, and Youth 7 February 1994 – 18 March 1996; for Employment and Training, Federal Affairs, Finance, and South West 18 March 1996 – 15 October 1996; for Finance 15 January – April 1997. Shadow Minister for Prisons 6 January 1999 to 20 January 2000.
Standing Committees
Member Standing Committee on Government Agencies September 1989 – January 1993; and Constitutional Affairs and Statutes Revision Committee 25 August 1992 – January 1993. Chairperson Estimates and Financial Operations Committee 10–29 April 1997; additional member to consider the Estimates for 1990–91 and for 1991–92.
Select Committees/Royal Commissions
Chairman Joint Select Committee on Parole 7 September 1989 – 28 August 1991. Member Select Committee on West Australian Police Service 2 December 1992 – 8 January 1993. Halden represented the Western Australian Branch of the Commonwealth Parliamentary Association at the 22nd Australasian and Pacific Region Conference, New Zealand, September 1991.
In 1992, Halden tabled a petition in the Legislative Council in the initial public act of the scandal which became known as the Easton affair. Investigating Halden's role in the affair was part of the brief of the Marks Royal Commission. Halden was charged with perjury before the Commission and was tried and acquitted in December 1998.
After parliament
Halden resigned from his position as MLC for the South Metropolitan District on 20 January 2000 in order to take up the position of Labor Party State Secretary. Halden resigned from his position as State Secretary of the ALP on 27 April 2001. He later started a lobbying office, representing clients seeking consideration from the government of Western Australia. In May 2008 he gave an interview to The West Australian which resulted in calls for the revocation of his lobbyist's licence. Halden had indicated that Public Service officers had occasionally been indiscreet and provided him with confidential governmental information. On 3 June 2008, the matter was referred to the Western Australian Corruption and Crime Commission.