Tony Abbott's use of a Washington Post interview to brand his Labor predecessors as ''wacko'' and ''embarrassing'' could set back his working relationship with the Obama adminstration, a leading US commentator says.
Norman Ornstein, an author and political scientist with the right-leaning American Enterprise Institute, said he ''winced'' when he read the interview in which Mr Abbott put the boot into the Rudd-Gillard government in unusually strong language for a foreign interview.
''It really does violate a basic principle of diplomacy to drag in your domestic politics when you go abroad,'' Dr Ornstein said. ''It certainly can't help in building a bond of any sort with President Obama to rip into a party, government and - at least implicitly - leader, with whom Obama has worked so closely.
''Perhaps you can chalk it up to a rookie mistake. But it is a pretty big one.''
Politicians around the world typically refrain from engaging in fierce domestic political argument when they are speaking to an overseas audience.
Dr Ornstein, a resident scholar at the AEI - one of Washington's oldest think tanks - was one of Foreign Policy magazine's 100 ''top global thinkers'' in 2012.
In the interview, Mr Abbott told The Washington Post that the former Labor government's conduct was ''a circus'' and was ''scandalously wasteful''.
''It was an embarrassing spectacle and I think Australians are relieved they are gone,'' he said.
Asked about Labor's plan to extend fibre to every household under the national broadband network, Mr Abbott said: ''Welcome to the wonderful, wacko world of the former government.''
Julia Gillard in particular forged what observers say was a warm and constructive relationship with Mr Obama, which included the deal to station US marines in Darwin. She was one of just 12 world leaders whose calls Mr Obama returned personally after they had called to congratulate him on his 2012 re-election.
Former diplomat and senior public servant John Menadue said it remained to be seen whether Mr Abbott could ''make the transition from a critic in opposition and an attack dog to a responsible and constructive prime minister''.
In 2007, then prime minister John Howard caused an international stir when he said al-Qaeda in Iraq would be praying for an Obama victory in the presidential race - a criticism of Mr Obama's plan to bring US troops home from Iraq.
Meanwhile, the White House has refused to comment on - or rule out - whether the US National Security Agency has ever tapped the phones of any Australian prime minister.
In the wake of revelations that the NSA may have bugged German Chancellor Angela Merkel's mobile phone, Fairfax Media asked the US government whether it could rule out ever bugging Australian leaders.
National Security Council spokeswoman Caitlin Hayden said: ''We are not going to comment publicly on every specific alleged intelligence activity, and as a matter of policy we have made clear that the United States gathers foreign intelligence of the type gathered by all nations.''
