Advisers to both Barack Obama and John McCain, the Democratic and Republican candidates, say they will seek to rebuild the image and influence of the US in the world after eight years of President George W. Bush, during which time old alliances have come under heavy strain.

When he travels to Nato's 60th anniversary summit in April, the new president will seek to overcome European doubts about sending more troops to fight the Taliban in Afghanistan and concerns about closer ties with Georgia and Ukraine. He will also try to thrash out a modus vivendi with Russia, take action against al-Qaeda safe havens in Pakistan and, perhaps most urgently, address Iran's nuclear programme.

It is in grappling with such issues that one of two markedly different philosophies of international affairs will make its debut on the world stage. Mr Obama calls for greater use of diplomacy to solve the world's ills. Mr McCain highlights his tough stance on Russia and autocracies around the world.