Vocabulary: reputation 詞匯：聲譽(yù)

The fall from grace of retired General David Petraeus, once America's most prominent post-9/11 military leader, has surprised a nation. In the past he's been held in high esteem and has even been mentioned as a future presidential candidate. But after an extramarital affair he had to step down as head of CIA.

"Generals have played a very central role in American politics," says Ron Chernow, a biographer of George Washington. "In Britain they get knighthoods. We reward them with political positions in high office."

The BBC's Daniel Nasaw says that America's cult of the general dates back to its founding years, when they had to defend the country from European invaders and native tribes.

No less than 10 US presidents have served as generals. They are seen as having worked their way up through the ranks, even from modest backgrounds, like Ulysses Grant and President Andrew Jackson. And they are perceived as unblemished by national politics and its backroom deal-making or potential for moral compromise.

The Vietnam War was so unpopular that none of its generals found later political success, but since the 1970s, Americans have managed to separate the individual soldier - and his presumed heroism - from the cause.

Few Americans look back on the Gulf War as a heroic national cause, but General Colin Powell was mentioned in the 1990s as a presidential candidate and later served as secretary of state. And General Norman Schwarzkopf became a figure of international renown.

Americans consider the military their most respected public institution: 78% say they have "a great deal" or "a lot" of confidence in the military, according to the 2011 Gallup poll.

But some commentators believe that it may change. Andrew Bacevich, research fellow at the Kroc Institute for International Peace Studies at the University of Notre Dame and a retired Army colonel, says that with General Petraeus' downfall, the American public can begin to wonder why after 11 years of war in Iraq and Afghanistan "we haven't won anything".