U.S. Democrats hope to use their national nominating convention in Denver, Colorado, this week to make the case that Barack Obama should be the next president of the United States.  Each night, Democrats gather in the convention hall under lofty themes like family, unity, national security and change.  As VOA National Correspondent Jim Malone reports, some of the themes are aimed at addressing Senator Obama's potential weaknesses as well as strengths.

Michelle Obama addresses the Democratic National Convention, 25 Aug 08

It was no accident that the featured speaker on the first night of the Democratic convention was the candidate's wife, Michelle Obama. 

"What struck me when I first met Barack was that even though he had this funny name, and even though he had grown up all the way across the continent in Hawaii, his family was so much like mine," she recalled.  "He was raised by grandparents who were working class folks just like my parents and by a single mother who struggled to pay the bills just like we did."

Senator Obama is trying to make history as the first African-American president.  But public opinion polls indicate he is having trouble connecting with the kinds of working class voters who generally supported Senator Hillary Clinton in the Democratic primaries.

Political analyst Michael Barone is in Denver, commenting on the convention for Fox News Channel. Regarding Obama's style, Barone says, "He tends to address issues in kind of a professorial way, showing his very considerable intellect and argumentative skills.  But people wonder whether or not he is really, in some sense, one of them culturally.  And I think if I was the Obama campaign, I would be trying to establish his links with ordinary American lives."

In addition to introducing Obama's life story and family to the American people, experts also say Obama has to reassure Americans that his lack of national political experience is not an obstacle to him becoming president and commander in chief.

Some of the liberal activist groups here in Denver are looking for something else from Obama: they want to know if he is tough enough to fight back against Republican attacks.

"What I think people like about him is the sense that he is a fighter, you know, that is someone who is going to go out there and take the fight to John McCain and really show some emotion about the issues we are working on," says Eli Pariser, who is with the liberal activist group MoveOn.org. 

In addition to addressing some of Obama's perceived weaknesses, Democrats will also try to seize on some of his strengths during their convention. Obama long ago cast himself as an agent of change during an election year in which large majorities of Americans say they want the country to go in a different direction.

With that in mind, Democrats were moved to tears by Senator Ted Kennedy's speech linking Senator Obama with the political legacies John and Robert Kennedy, his late brothers. 

The cancer-stricken Kennedy vowed, "This November, the torch will be passed again to a new generation of Americans.  So with Barack Obama and for you and for me, our country will be committed his cause.  The work begins anew, the hope rises again and the dream lives on." 

Change will be the theme at the end of the convention on Thursday when Senator Obama gives his highly-anticipated acceptance speech before a worldwide television audience in a football stadium near the convention hall here.

Minnesota delegate Travis Burton at the DNC

Minnesota delegate Travis Burton says Obama's focus on change has tremendous appeal even for those who initially supported his rival, Senator Clinton.  

"This is why I have got all these Obama buttons even though I am a Clinton delegate.  It is because he is taking the time to actually work for the country.  Initially, I was a little apprehensive about change, change, change, you know, everybody runs on change.  But he is really trying to do something," he said. 

The Republicans have already laid out the themes for their convention next week in St. Paul, Minnesota, where Senator John McCain will be formally nominated.  The Republicans will focus on service and love of country, reform, prosperity and peace.