The rollercoaster ride of Jay Weatherill's South Australian premiership has taken another dip this week, after a parliamentary defection cost his Labor government its one-seat majority. 

The resignation of Frances Bedford from the ALP has been a long time coming -- much of her two-decade career has been spent pursuing left-of-centre positions that have often caused discomfort for the party leadership.

There have been intermittent suggestions over the years that she might end up pursuing such interests free from the bonds of party discipline -- either on her initiative to protest against heavy-handed law-and-order policies, or in response to a move against her preselection.