Nick Clegg has insisted that Britain must restore its reputation in the world after the foreign policy mistakes of the former Labour government.
• Deputy Prime Minister Nick Clegg addresses the 65th General Assembly of the United Nations in New York
In a thinly-veiled reference to the Iraq War, the Deputy Prime Minister said that the UK has learned "the hard way" that democracy cannot be imposed at will.
The Conservative-Liberal Democrat coalition would be "hard-headed and realistic" in its approach to the rest of the world, he told the United Nations general assembly in New York yesterday.
Mr Clegg was standing in for David Cameron at the gathering as he visits the US for the first time as Deputy Prime Minister.
The Deputy Prime Minister also claimed that the current Strategic Defence and Security Review is reshaping policy to address new threats that were less visible or predictable.
"Today the threats to our security are not rooted in specific states, are more fluid, and often less visible - terrorism, organised crime, or attacks from cyberspace," he said.
"We must judge our security not by our ability to deal with what we know, but how able we are to respond to unpredictable threats."
As well as attending the UN, Mr Clegg has used the trip to the US to cement relations between the Coalition and the Obama administration.
He bumped into President Barack Obama at the UN on Wednesday and held more than two hours of talks with Vice President Joe Biden at the White House on Thursday.
Mr Clegg and Mr Biden discussed not only the strategy in Afghanistan but also British and American domestic policies.
Their meeting was "warm and productive" and their respective aides would be staying in "close touch" in the future, a spokesman for Mr Clegg said.