The quintessential career politician, he had come more or less straight from student politics at Adelaide University to the real thing in Canberra - a fact his critics say, is all too evident.

Yet for all his knowledge, his parliamentary guile and his demonstrable intellectual power, Pyne has distinguished himself so far as the minister most likely to be over-ruled by his prime minister. That doesn't mean his future is in doubt, it is not. But he must be careful.

Last week, he set the hares running with his thought bubble over recouping outstanding HECS-HELP loans from the estates of deceased students. Abbott, alive to the dangers, killed the idea dead (if not buried and cremated).

It would have been bad enough if this was just an unwelcome distraction from a difficult post-budget sales task struggling to stay afloat. But Pyne's detractors are now talking of a pattern. They cite politically difficult moments when subsequent ''clarifications'' were required to steady the ship.

In November last year for example, Pyne overplayed the government hand telling a compliant media host, ''Boats have been turned back''. It was precisely the kind of direct statement Scott Morrison, the Minister for Border Protection, was refusing to discuss as a so-called ''on water matter''.