May 14 (Bloomberg) -- John Edwards, whose own bid for the Democratic presidential nomination ended in January, will throw his support behind former rival Barack Obama, the Illinois senator's campaign announced.

Edwards is scheduled to endorse Obama at a rally in Grand Rapids, Michigan, this evening. The move is a blow to New York Senator Hillary Clinton, who, along with Obama, had sought backing from Edwards.

``This is one of those endorsements that really matters,'' said Stephanie Cutter, an unaligned Democratic strategist who worked on Senator John Kerry's 2004 presidential campaign. ``It's another sign that the primary race is coming to an end.''

Mo Elleithee, a spokesman for Clinton's campaign, said she will continue to fight for the nomination. ``We have great respect for Senator Edwards, but as the voters of West Virginia showed last night, this race is far from over,'' he said.

Obama is leading Clinton in the chase for delegates who will choose the party's presidential candidates, and is closing in on clinching the nomination. He has backing from 289 of the Democratic superdelegates, compared with 275 for her, according to lists and announcements from both campaigns.

Obama also leads in pledged delegates 1,598 to 1,446, according to an unofficial count by the AP, meaning he needs to win fewer than 150 additional delegates to secure the 2,026 needed to clinch the Democratic nomination.

More Endorsements

Clyde Wilcox, a government professor at Georgetown University in Washington, said the Edwards endorsement will be ``important if it triggers a group of superdelegates who had backed him to announce'' their support for Obama.

The endorsement follows Obama's 41-point loss to Clinton in the West Virginia primary, which Clinton argued showed she's better able to draw working-class and rural voters. Those are the same groups that Edwards targeted in his campaign.

Getting Edwards is an ``important step for Obama to start his appeal to the white working-class voters who have thus far eluded him.'' said Julian Zelizer, a history and public affairs professor at Princeton University in Princeton, New Jersey.

Edwards, 54, quit the race Jan. 30 after failing to score a victory in the first four nominating contests and remained on the sidelines as Clinton and Obama battled through the primaries and caucuses.

A former trial lawyer, North Carolina senator and the 2004 Democratic vice presidential nominee, Edwards ran with strong backing from organized labor groups. Still, he was unable to match Clinton and Obama in fundraising and media attention.

His former campaign manager, David Bonior, who served in the U.S. House from Michigan, endorsed Obama last week.

The Democratic nominee will face a general election campaign against Arizona Senator John McCain, the presumptive Republican candidate.

To contact the reporter on this story: Julianna Goldman in Grand Rapids, Michigan, at jgoldman6@bloomberg.net.

Last Updated: May 14, 2008 18:20 EDT