Without much hard evidence, a consensus across the political class has it that Shorten's stellar rise from laggard to genuine contender has stalled some way short of the race's end. Plateaued.

Opposition Leader Bill Shorten. Credit:Alex Ellinghausen

It is certainly true that early gains for Labor in 2016 were big whereas recent progress, if any, has been incremental. But this is normal. Australian elections are frequently tight. Indeed, the closer the contestants get to polling day, and to 50-50 standing, the smaller the likely movements in public sentiment. The law of diminishing returns applies with "uncommitted" voters shrinking to an ever smaller fraction of the electorate.

Elections have been won and lost on these modest shifts. But you have to be close enough in the first place to benefit.

Shorten's recovery in 2016 has been remarkable after a post-Tony Abbott plunge in late 2015 had reversed his party's lead of 54-46 (in the August Fairfax-Ipsos poll) to be 56-44 down under Turnbull by November.