I heard Andrew Coyne say that whoever comes in third on the first ballot at the convention could be deciding factor. I think he was writing Topp, Ashton and Singh off and assuming Mulcair would come in first and Nash in second on the first ballot. He said that if Cullen comes in third he could throw his support behind Mulcair and give him the leadership. But if Dewar comes in third he could support Nash and push her into first. Interesting scenario.