US election: the key moments of the 2012 campaign August 11: Paul Ryan As Republicans begin to openly despair at their fading chances of taking the White House, Mr Romney looks for a running mate who can unite the party and invigorate the base. He settles on Paul Ryan, the young Wisconsin congressman best known for his radical plan to slash government spending. The official announcement is made in front of a World War II battleship and electrifies conservatives who are wary of their candidate. Mr Ryan proves steady on the trail but the choice ultimately makes little impact with voters. September 11: Benghazi Christopher Stevens (Reuters) Islamist militants overrun the small US consulate in eastern Libya, killing Ambassador Christopher Stevens and three other Americans. The White House initially claims the attack began as a peaceful protests against an anti-Islamic film but is later forced to admit it was the work of terrorists. Barack Obama's credentials on national security are damaged as it emerges that US diplomats in Libya repeatedly asked Washington for more security and were ignored. Republicans accuse the administration of a cover-up and of failing to heed clear warnings the consulate was under threat. September 17: 47 per cent Secretly-filmed footage emerges of Mr Romney addressing donors at a closed-door fund-raiser, where he appears to dismiss 47 per cent of Americans as government dependants who will vote for the President so they can stay on welfare. "My job is not to worry about those people," he says. The politically explosive video appears to confirm stereotypes of the Republican as a heartless plutocrat and is put at the centre of Democrat attacks. Mr Romney later says his comments were "completely wrong." September 5: Bill Clinton X Despite their slim lead in the polls, Democrats gather at their party convention in North Carolina feeling increasingly anxious about holding the White House. But their anxieties are blown away by Bill Clinton's barnstorming 50-minute speech to the party faithful. The former president mixes rhetoric with a barrage of statistics as he accuses Republicans of betraying the middle class and rallies the party to fight on. Mr Obama embraces him at the end of his address and in the following days Democrats' poll numbers shoot upwards. October 3: First debate Mr Romney limps into the first debate trailing badly in the polls and with pundits preparing to write his political obituary. But over 90 minutes on a stage in Denver he delivers a powerful performance that sends shock waves through the election. Striking a newly-moderate tone, he is judged to have won by large margins. By contrast, Mr Obama looks rigid and unhappy on stage, often stumbling over his words and failing to land any significant blows. Days later the Republican overtakes the President in the polls for the first time. October 5: Jobs report The unemployment rate drops abruptly to below eight per cent for the first time since Mr Obama took office, jolting both campaigns and undermining one of the Republicans' most effective lines of attack. The President returns to the campaign trail with renewed vigour, arguing that his policies are working and that "this country has come too far to turn back." Republicans claim that the recovery is still too slow, but privately admit that the economy's progress is strengthening Mr Obama's case for re-election. October 29-31: Hurricane Sandy As Hurricane Sandy menaces the Eastern seaboard, Mr Obama cancels his campaign rallies and returns to Washington. The storm makes land in New Jersey, causing more than 100 deaths and leaving millions without power but the President wins plaudits for the government's agile response. He makes a high-profile trip to the devastated Jersey Shore, where he meets survivors and is embraced by Chris Christie, the state's Republican governor. In the days after the storm, Mr Obama's poll numbers begin to creep ahead.