From the Prime Minister’s statement today on last night’s by-election results.
“Though it is rare for a governing party to win by-elections, we are buoyed by the fact that the Conservative Caucus in the House of Commons has increased.”
As noted previously, and according to Wikipedia’s records, heading into last night 31 seats last held by the incumbent government have been contested in by-elections over the last 30 years, 22 of those—71%—remaining with the government.
Since taking office in 2006, the Harper government has now picked up four seats that were held by opposition parties. The Chretien government won an equal number of opposition seats between
1988 1993 and 2004. The Mulroney government retained six two of its nine six seats and picked up two opposition seats.* You have to go back to the The Trudeau government to find an incumbent administration that significantly struggled in by-elections—between 1968 and 1979 1984, 20 25 Liberal government seats were contested, 11 13 of those going to the opposition by my count. Over But over the same period, the Liberals picked up three four opposition ridings.
Going back to 1968 then, a total of
57 53 seats last held by an incumbent government have been contested, 34 32 of those retained by the incumbent. Over that same period, the governing party has picked up a dozen seats held by opposition parties.
*Wells checked my math and it seems I took a slightly wrong turn somewhere in the 80s. Larger trend still holds.