An optimistic federal Opposition Leader Brendan Nelson has met the campaign teams of both US presidential candidates - despite doubts over how long he will remain leader.
The US election is scheduled for November, while in Australia persistently poor opinion polls are casting doubt about how long Dr Nelson's leadership will last.
The possibility of former treasurer Peter Costello making a tilt for the leadership is expected to be resolved next month when he releases his memoirs.
Dr Nelson, who is in the US as part of a 10-day tour, told reporters in Washington he had met with members of the campaign teams for both Barack Obama and John McCain.
"Well, the trip through London and New York and Washington has been to canvass political, economic, defence and foreign policy issues," he said.
Dr Nelson brushed off questions about his leadership.
"Well, I don't comment on any of that, I just do my job," he said.
He declined to say whether he had kept in touch with his Liberal colleagues while overseas.
Dr Nelson said he expected Mr Costello to make a decision fairly soon.
"I'm sure in the not too distant future he will tell Australians what he intends to do," he said.
On climate change, Dr Nelson reiterated his claim that western nations would struggle with emissions trading unless developing nations got on board.
Both US presidential candidates have promised to implement emissions trading, but Dr Nelson warned it could be tough for them.
"I don't think anybody should underestimate how politically difficult it is going to be in the United States to pass legislation for an emissions trading scheme if there is not commitment and action coming from the other major emitters throughout the world," he said.
"One of the key messages that from those that I've spoken to in both Europe but particularly the United States is that we cannot afford to basically transfer money from low-income American or Australian households into the pockets of already wealthy people who are running utilities in other countries."
