The 39th Canadian Parliament was in session from April 3, 2006 until September 7, 2008. The membership was set by the 2006 federal election on January 23, 2006, and it changed only somewhat due to resignations and by-elections. The Parliament was dissolved on September 7, 2008, with an election to determine the membership of the 40th Parliament occurring on October 14, 2008. There were two sessions of the 39th Parliament: Overview The 39th Parliament was the longest minority government led by any federal government excepting Mackenzie King's Liberal Party government in the 14th Parliament, which fluctuated between majority and minority status. No other Conservative minority had previously lasted a full year, and only Lester B. Pearson's governments had lasted more than two. The 39th Parliament was controlled by a Conservative Party minority, led by Prime Minister Stephen Harper and the 28th Canadian Ministry, which assumed power on February 6, 2006. The Official Opposition was the Liberal Party, led first by interim leader Bill Graham, and then by Stéphane Dion for the remainder of the Parliament's life. The Speaker was Liberal Peter Milliken. Milliken was re-elected as the Speaker of the House for the 39th Parliament on April 3, 2006. The Speaker only votes in a tie, and, as Milliken is a Liberal, the Liberal caucus was effectively reduced by one. This, along with the defection of Wajid Khan to the Conservatives enabled the Conservatives to pass legislation with the cooperation of any one of the three opposition parties: Liberals, Bloc Québécois, or New Democratic Party (NDP). The party standings as of the election and as of dissolution on September 7, 2008, are on the table below. Between these events, five members of the House of Commons crossed the floor, one died, twelve resigned, and nine members were elected in by-elections to fill vacancies, leaving four vacancies at dissolution. In that same period, two senators died, six reached the mandatory retirement age of 75, four resigned, and two were appointed to fill vacancies, leaving fifteen vacancies at dissolution. Step-by-step changes are listed in the Members section. See List of Canadian federal electoral districts for a list of the ridings in this parliament. The Parliament was dissolved by Governor General Michaëlle Jean on the advice of Prime Minister Stephen Harper on September 7, 2008. The general election for the members of the 40th Parliament of Canada was held on October 14, 2008.