Much rides on the historic Democratic convention opening Monday in Denver, Colorado.  US Senator Barack Obama, 47, the first African-American to secure a major-party presidential nomination, is a relative newcomer with four years in national politics, no executive experience and limited foreign exposure.

He is expected to use four days of prime-time broadcasts to fill in the gaps. He is aiming to convince voters that he's a patriotic American family man who can be trusted to make the right decisions about national security and lead the economy away from the brink of recession.

By the time Obama delivers his acceptance speech before 76,000 people at Denver's Mile-High Stadium on August 28, he will also have put a strong spotlight on Senator Hillary Clinton in a bid to heal the lingering wounds of their hard-fought primary campaign.

On the surface, this election is tailor-made for the opposition centre-left Democrats.

The country remains bogged down in the Iraq war, while mired in a slowing economy that coupled with rising inflation continues to erode the buying power of average Americans. Meanwhile, Republican President George W Bush's popularity ratings are among the lowest in the history of modern survey research in the United States.

Yet Obama has lost traction in national surveys in the last several weeks of summer, with his edge over presumptive Republican nominee John McCain, 71, trimmed to 1.5 percentage points in this week's average of the latest polls.

Analysts point out that there's nothing unusual about the tightening race, because most voters don't start thinking seriously about the presidential elections until after the two major-party conventions - the Republican convention is September 1-4 in St Paul, Minnesota.

Democratic officials are worried about the slump, which follows weeks of McCain's high pressure attacks over the whirlwind Obama tour of Europe and the Middle East and charges that Obama's ambition dictates his position on war and peace - a message seen by some as "pretty tough stuff."

Analyst Thomas Mann of the centre-left Brookings Institution, a Washington-based think, is optimistic that Obama "retains the huge advantage of being a Democrat and member of the out party at a time of deep public discontent."

Mann believes Obama is headed for a double-digit percentage victory in November if he is able to refocus the agenda "away from him personally" and onto the economy, which according to a CNN opinion poll this month dominates nearly three-to-one as the issue that could sway voters on November 4.

Obama must do more to link McCain to Bush. The senator from Chicago needs to "reassure people that he's able and has good judgement and is trustworthy with responsibilities of the office," Mann said.

More a showcase for the party than a competitive forum for candidate selection these days, the Denver convention will be sculpted to put forward the best face of the Democrats, who have traditional advantages with ethnic minorities and women.

During the week, Democratic former presidents Jimmy Carter and Bill Clinton are scheduled to speak, and the convention will see a videotaped message from iconic Senator Edward Kennedy, who is suffering from brain cancer.

As Democrats seek inroads with religious voters, among whom leftwing candidates have long done poorly, Obama's campaign has proposed a campaign platform that would soften the party's stance on abortion rights and open the door for more support for women who choose to have their babies, media reports said.

Both Nancy Keenan, president of Pro Choice America, as well as Senator Bob Casey Jr, an opponent of legalized abortion, will be speaking.

Notable by his absence for the first time in a generation will be civil-rights activist Jesse Jackson, a black minister who infamously spoke - during a break in a television show - of castrating Obama for his support of government funding for faith-based charities.

The gaffe laid bare a deep generational shift among the country's black leadership that has emerged with Obama's candidacy.

Two milestones in US political history will be observed during the convention week in the city at the foot of the Rocky Mountains.

Obama's Thursday acceptance address will be made on the 45th anniversary of civil-rights activist Martin Luther King Jr's I Have A Dream Speech. The 2000 Democratic presidential candidate, former vice president Al Gore, will speak earlier on the same night.

Earlier in the week, Hillary Clinton's address on Tuesday will be made on the 88th anniversary of passage of the constitutional amendment that gave women the right to vote. Obama's campaign has granted Clinton such prominence in response to demands that her history-making candidacy be recognized, after she became the first woman to come so close to a major-party US presidential nomination.

Clinton has already declared her support for Obama and campaigned for him, but many of her supporters have not made the transition.