Iowa Democratic Party officials said that with all of the delegates picked, Obama claimed 52 percent of the delegates elected at county conventions on Saturday, compared with 32 percent for Clinton.

Some of the delegates picked at Saturday's conventions were sticking with Edwards, even though he's dropped from the race since Iowa held its caucuses in January. Democratic Party projections said the results mean Obama increased by nine the number of delegates he collects from the state, getting a total of 25 compared with 14 for Clinton and six for Edwards.

Twelve automatic delegates bring the state's total to 57. Obama has been endorsed by four of those and Clinton three, with the remainder uncommitted. Also Saturday, California's Democratic Party finalized the delegate counts from its Feb. 5 primary. Clinton picked up two more pledged delegates, raising her state total to 204; Obama gained five, raising his figure to 166.

Counting Saturday's new figures from Iowa and California, an Associated Press delegate tally showed Obama with 1,617 delegates and Clinton with 1,498.

Interviews with dozens of undecided superdelegates — the elected officials and party leaders who could hold the balance of power for the nomination — found them uncertain about who, if anyone, would step in to fill a leadership vacuum and help guide the contest to a conclusion that would not weaken the Democratic ticket in the general election. While many superdelegates said they intended to keep their options open as the race continued to play out over the next three months, the interviews suggested that the playing field was tilting slightly toward Mr. Obama in one potentially vital respect. Many of them said that in deciding whom to support, they would adopt what Mr. Obama’s campaign has advocated as the essential principle: reflecting the will of the voters.