guarnieri was elected as member of parliament in 1988 in a fairly close race with her progressive conservative opponent laurie pallett. she won all her subsequent elections in mississauga east and after 2004 in mississauga east—cooksville by wide margins. a longtime martin loyalist, she was a relatively obscure backbencher during the chrétien era. martin named her associate minister of national defence and minister of state for civil preparedness in his first cabinet. she moved to veterans affairs on july 20, 2004.