In all likelihood, Cory Bernardi's expected breakaway from the Liberal Party will fail to achieve anything beyond hostile headlines, fevered speculation about who might follow him, and an immediate morale blow to a beleaguered Coalition.

What it will not do is lead to an aggregate increase in the non-Labor/conservative vote. Instead, it will ensure a fragmentation of that vote and, therefore, its diminution.

Presumably, any Bernardi gains would derive from discrediting institutional conservatism's official candidates in the electoral marketplace - Malcolm Turnbull principally, but others by association from Scott Morrison, Barnaby Joyce and Peter Dutton to Tony Abbott.

In so doing, the Bernardi split is a gift to Labor and one more akin to an annuity than a lump sum. It could pay out over years.