This was always going to happen for two reasons. The first is many in the Liberal and Nationals leadership are convinced the long term gadfly and Malcolm Turnbull critic gamed the system by using last year's full Senate election to secure a term that does not end until June 30, 2022.

The second is while Bernardi's not entirely unexpected departure does not represents an existential crisis for the Coalition in the way the 1955 Labor split did for that party, every effort has to be made to ensure no other serving parliamentary members jump on to what is a very small bandwagon.

The real betrayal is of the voters of South Australia who delivered the Liberals a clear majority of the Senate vote in that state just seven months ago. Bernardi, whose ongoing ratbaggery had seen him demoted to second place on the ticket, was still returned comfortably.

This would not have been the case if he had stood as an independent or "Australian Conservatives" candidate.

Looking ahead it would, at first glance, appear hard for Bernardi to secure re-election when he goes to the polls in five-and-a-half years, by which time he will have been in the Senate since 2006. South Australia's Senate voting patterns have been skewed by the strong support for the Xenophon party, Family First remains a factor and One Nation campaigned strongly in 2016.

All of these groups are, to a greater or lesser extent, courting the same post-Brexit and Trump "protest vote" Bernardi has targeted.

That said, South Australians have a history of voting outside the boxes and the recent departure of Bob Day has created a vacuum Bernardi may be able to exploit to his advantage over time.

While Tuesday's defection is viewed by many as the latest body blow in what is shaping up to be an "annus horribilis" for the Turnbull Government, it is not without its upside. Bernardi has been a wild card and destabilising influence within the Coalition since first entering the Senate. His first open challenge to Malcolm Turnbull's authority occurred in 2008 on the issue of same sex relationships.

Since then he has become a lighting rod for discontent within Liberal ranks and, thanks to his uncompromisingly conservative views on a wide range of social issues, a poster boy for everything many love to hate about the Liberals in the 21st century.

Bernardi's departure has drawn a line in the sand many, if not all, of his former well-wishers won't dare to cross. It remains to be seen if Malcolm Turnbull is able to seize the moment to steer his Coalition back to the political middle ground. The survival of his leadership depends on it.