The Nationals' frontbench exodus has exposed a Coalition agreement that has been operating on expectations of loyalty and trust that no longer appear to exist. The political alliance has effectively been on borrowed time ever since the rural party last year temporarily split from the Liberals in an attempt to secure an exemption from the long-running convention of shadow cabinet solidarity. The net-zero debate seemed to be the most likely issue to destroy the tenuous accord after it was stitched back together. Arguably, no-one could have guessed the trigger would instead be the federal parliament's response to a terror attack....