any parliament is going to yield a trickle of mps who decide to bow out before the next election, be it due to retirement, health problems or the oft-cited desire to “spend more time with family.”
in normal times the departures are pretty evenly shared among the various parties.
between the 2015 and 2019 elections, for instance, 44 mps decided not to run for re-election; 14 conservative, 19 liberal and 11 ndp.
go back to the period between the 1997 and 2000 federal elections – both of which are won by the liberals – and you’ll find an evenly distributed mix of 21 mps who decided to bow out; seven for the reform party, six for the liberals and eight bloc québécois.
but these ratios are known to shift dramatically when an incumbent is lurching towards an election they’re likely to lose.
the textbook example belongs to 1993, when the progressive conservative government of brian mulroney began scraping record lows of unpopularity before ultimately being defeated by the liberals under jean chrétien.
in the months preceding election day, 50 progressive conservative mps announced they wouldn’t be running for re-election – roughly a third of the caucus. this was against just six liberal and six ndpers who did the same.