As Mayor of Charlesbourg, Mercier fought against municipal reorganization in Quebec City.
[3] Mercier considered retirement in 2004, but ultimately decided to stand in the 2005 elections.
After Boucher's death in 2007, Mercier found himself in a more disagreeable situation with the new mayor Régis Labeaume.
[5] Mercier had been active in the Union Des Municipalités Du Québec (UMQ), where he served as President from 1990 to 1993.
He sat on the board of directors for the UMQ as a representative of the caucus des grandes villes.