IN January, Tony Abbott seemed finished as Prime Minister. But how things have changed. Now the leader under pressure is Labor’s Bill Shorten. Just ask his smiling deputy, Tanya Plibersek. The mischief began last week, with Shorten away and Plibersek acting leader. First, Plibersek declared Labor should now force its politicians to vote for gay marriage, rather than allow a conscience vote. Many Labor MPs were outraged. MPs — including devout Christians — who would feel morally obliged to vote against party policy could be expelled under Labor’s rules. Labor could split. Shorten, on his return, quickly rejected Plibersek’s bullying...