Queensland Nationals Senator Barnaby Joyce has drawn a line in the sand: he won’t be supporting Prime Minister Kevin Rudd’s emissions trading scheme.

If Malcolm Turnbull’s shadow Cabinet decides to give critical support to the scheme, Joyce will oppose them on the floor of the Senate.

If his own National Party colleagues decide to give qualified backing to Labor’s ETS project, he will defy them and vote against — even though he is the Nationals Leader in the upper house.

In other words, Joyce is on a collision course with the Coalition leadership, the Liberals and his own Nationals over ETS. It could rock the Coalition: senior Liberals are demanding that the Nationals expel Joyce (and anyone who supports him).

If Joyce and his close-knit supporters are removed from the Nationals whip, they intend forming their own parliamentary grouping based on the principles of the old Country Party.

Joyce sets out his opposition to the Rudd plan in an lengthy article he has written for the Queesland-based rural website agmates.com edited by Steve Truman.

He describes the proponents of ETS as religious zealots who don’t have the science to back up their doom-laden claims. “Those who dare to question are held as heretics,” he writes.

“I don’t pretend for one moment to be a scientist but in my role in the Senate it is implicit in my job to be a sceptic, to question and to consider all sides and be open to the views of many rather than one view.

“My current concern with the emissions trading scheme is that a religious fervour has built up around the altar of global warming. Those who serve at the altar have become ruthless in their denigration of alternate views.”

In old-fashioned populism we haven’t seen since Sir Joh Bjelke-Peterson, he claims the scheme is nothing more than a tax-raising enterprise which will punish people’s pockets and jobs.

The trouble is that a large sector of rural Australia as well as climate change skeptics in the cities are listening: it is music to the ears of the mining industry too.

Meanwhile, the Labor Party can sit back and watch the squabble within the Coalition flare into civil war. As Malcolm Turnbull himself as acknowledged, Coalition disunity is electoral death.