Tony Abbott’s resignation must surely mark the end for Malcolm Turnbull’s leadership and therefore, in all probability, for the deal with Labor over the ETS.
Ultra-optimistic scenario: Turnbull quits and Abbott is installed, the deal is cancelled and Rudd calls a double dissolution based on the original bill, winning easily. Since the original bill clearly needs amendment he doesn’t use the joint sitting mechanism but instead makes an agreement with the Greens who now have the balance of power.
Rudd’s preferred scenario: Turnbull holds on long enough to deliver seven senate votes tomorrow and pass the watered-down ETS. He is promptly rolled and the Liberal party splits. Abbott as new leader, starts with a commitment to repeal the scheme, but abandons it because this is the last thing big business wants. Labor reduces the divided opposition to rump status at the next election, and ends up dealing with three or four different parties in the Senate, needing only one to get its legislation through. This is probably more plausible than mine, but the timing will be very tight tomorrow. The decision is to be made at 3:45pm, apparently.