Change is the key 

One year ago, it was very hard to imagine that Obama, a young politician without a strong political base and little known to the public can defeat Hillary Clinton, the heir-apparent of the Democratic Party.

Supporters cheer as US Democratic presidential candidate Senator Barack Obama (D-IL) speaks at his South Dakota and Montana presidential primary election night rally at the Xcel Energy Center in St. Paul, Minnesota June 3, 2008. (Xinhua/Reuters Photo) 

As former first lady who has the backing of the majority of party elders, Clinton was 30 points ahead over any rivals in the party and raised more money than anyone else in the campaign.

Some analysts attributed her defeat to her flawed strategy of focusing on big states and her wishful thinking for a quick victory. When the contest turned out to be tougher and longer than expected, her campaign did not know how to cope with the situation.

As a result, Obama won 11 consecutive contests after the Super Tuesday of February 5 and formed an insurmountable lead in the tally of delegates.

But some analysts said losing touch with voters is a far more serious flaw for Clinton's campaign. While highlighting her experience and strength as a candidate, she failed to cater to the general desire for change among a majority of democratic voters.

By contrast, Obama captured the voters' mentality by describing himself as a "candidate of change".