Brennan was a Fianna Fáil member of Limerick County Council for over 20 years, and seved as chairman of the council in 2000. He was nominated by the Taoiseach to Seanad Éireann in 2002, but left the party on 29 April 2004 to join the Progressive Democrats (PDs), after a dispute arising from the end of the dual mandate. Under the Local Government Act 2001, members of the Oireachtas could no longer serve as local councillors, and Brennan's wife Rose sought a Fianna Fáil nomination to stand for election as his successor in the Bruff Electoral Area. She did not win a nomination, and speculation that she would be impised as a candidate by the national party, that did not happen. Rose also defected to the Progressive Democrats, and was elected as a PD County Councillor for Bruff. She subsequently became vice-cathaoirleach of Limerick County Council.
In the 2007 General Election Brennan stood as a candidate for the Progressive Democrats in the Limerick West constituency. He polled a respectable 1,935 first preferences, but did not win a seat. Brennan was not returned to the Senate in the 2007 Senate election. He remains a major figure locally within the party and the constituency.
Extra funds pledged: from infrastructure to childcare ; The following is a selection from the main features of the Progressive Democrats' manifesto
Apr 22, 2002; Ecomomy The Progressive Democrats are giving three clear guarantees on fiscal policy if returned to government after the...
No sign of the hairshirt as parties offer bland prospect for years ahead ; The new Programme for Government, the marriage vows between Fianna Fail and the Progressive Democrats, has omitted a pledge to cut specific spending programmes, writes Denis Coghlan
Jun 05, 2002; With Government spending up 22 per cent on last year, everyone was anxious to know how nasty Charlie McCreevy's new medicine was...