WASHINGTON -- Sen. Barack Obama, bidding to become the first African-American to win a major-party presidential nomination, signaled his entry into the 2008 presidential contest yesterday.
The Illinois Democrat, who joins the race near the top of a crowded field, made it clear that he would run as an outsider. In a brief online video announcement, he used the word change five times, criticized Washington's bitter partisanship and cast his decision to form an exploratory committee as a response to those "hungry ... for a different kind of politics."
Obama, who is expected to formally declare his candidacy next month, starts out as a serious contender in a nomination chase so top-heavy with talent that it has relegated a number of well-regarded and more experienced candidates to secondary status - or forced them to quit altogether - more than a year before the first primary vote has been cast.
Party strategists said Obama's strength in early polling and his fundraising potential exceed those of most other '08 Democrats. But the liberal senator faces a number of hurdles, including a lack of seasoning as a presidential campaigner and a still-undefined national image.
"His biggest challenge will be to show he has gravitas," said Kenneth Baer, a Democratic strategist, and to avoid being defined in negative terms by his opponents or the news media. "Nobody knows his record. Nobody really knows the Illinois Senate record, and believe me, all of that will be coming out in bucketfuls."
A biographic video, posted yesterday on Obama's campaign Web site, tried to fill in some of the blanks. It indicated, for example, that Obama plans to emphasize the results he achieved during two terms as an state legislator on issues such as the death penalty, racial profiling and welfare reform.
The formal declaration of his candidacy is set for Feb. 10 in Springfield, the Illinois capital - distancing himself, in geographic terms, from the old-fashioned politics of Chicago, where Obama makes his home; but cozying up to the legend of Abraham Lincoln as well as offering a chance to promote his record as a state senator.
Democrats active in other campaigns, or watching from the sidelines, said Obama's candidacy poses a significant threat to the other leading candidates, Sen. Hillary Rodham Clinton of New York and former Sen. John Edwards, the 2004 vice presidential nominee from North Carolina.
Clinton, widely regarded as the early front-runner, is counting on support from African-Americans, who strongly backed her husband, Bill, in his two presidential runs and who historically cast about one of every four votes in Democratic primaries.
"Now, all of a sudden, she has a competitor," said Democratic pollster Paul Maslin, an adviser to Indiana Sen. Evan Bayh, who abandoned the 2008 race last month shortly after being outshone in New Hampshire by Obama.
Maslin, who advised a Democratic rival in Obama's 2004 Senate primary campaign, said early polls in that contest showed Obama getting only about half the black vote. He wound up taking 85 percent, once it became clear that he had a serious chance to win.
Edwards, a vocal anti-war candidate since renouncing his Senate vote to authorize force against Iraq, is running well in Iowa, which holds the first delegate contest. But Obama, from neighboring Illinois, is the only major candidate in the Democratic field who opposed the war from the start.
"We're still mired in a tragic and costly war that should have never been waged," said Obama, appearing tieless in his video announcement, whose low-key tone and informal setting appeared designed to convey an image of a new and different type of politician.
"It's not the magnitude of our problems that concerns me the most," he said. "It's the smallness of our politics."
He criticized "our leaders in Washington" who "seem incapable of working together in a practical, common-sense way. Politics has become so bitter and partisan, so gummed up by money and influence, that we can't tackle the big problems that demand solutions."
Anita Dunn, who has advised Obama's political action committee but is currently neutral in the 2008 contest, noted that he has never had to face tough competition in a campaign before.
A presidential campaign "is like climbing Mount Everest," she said. "People start out with all this enthusiasm, and by the end, they're just trying to survive. It's miserable and you can't breathe the air and you can't eat and your brain cells are dying. That's why those who get to the top tend to be those who have done it before."
Other Democrats said Obama would now have to shift away from "his Kumbaya message," as more than one put it, and start laying out the specifics of what he would do as president.