It's our Prime Minister's birthday today. In a spirit of charity, we should wish him many happy returns. We must acknowledge, though, that, at the moment, he's not in a sweet spot politically. He never will be.

To thrive in the job, a prime minister must be a canny politician. Yet Malcolm Turnbull, even though he has held the office for more than two years, has only ever exhibited a limited mastery of the art and craft of politics.

Evidence of Turnbull's fitful strike rate as a political performer can be drawn from past decades as well as more recent events.

Back in 1999, a masterful John Howard easily outfoxed Turnbull's badly organised republican campaign. In an eerie near-reprise 18 years on, the poorly plotted same-sex marriage postal survey looks like being carried partly because Turnbull is running dead on the issue.