In Sydney today, former Labor prime minister Paul Keating said: “Mr Costello has made not one valuable structure change in the Australian economy in the 12 years he was treasurer. He’s a guy without imagination and he is a guy without courage.”

Peter Costello has had two chances to lead the Liberal Party: in 1994 and after last year’s poll defeat. Now he has a third. But Costello has never wanted to be leader. He has just wanted to waltz into the prime ministership.

The reform of detention testifies to the transformed political climate since 2001, with few boat arrivals in recent years. But Immigration Minister Chris Evans knows that more boats will come and this is Australia’s permanent challenge. In an interview with The Australian, he argued the new detention policy is geared to this reality.

“If you don’t understand the GST, don’t vote for it.” That’s the line Paul Keating used days out from the 1993 election. It helped turn the poll. But you can’t imagine Brendan Nelson saying something similar about the emissions trading scheme. You need authority.