They believe Rep. Pelosi is for Sen. Obama, rather than impartial as she insists. Their aim was the audience of uncommitted superdelegates.
The reasons say a lot about these superdelegates' calculations for the November elections -- the presidential one, or their own.
The 795 superdelegates, who can vote for any nominee, fall into one of two groups -- the elected and the unelected.
Sen. Obama has taken the lead among elected officials, and Monday got the endorsement of New Mexico Sen. Jeff Bingaman, though Sen. Hillary Clinton will counter Tuesday with a commitment from Gov. Mike Easley, whose North Carolina holds the next primary. Sen. Clinton still leads by double digits among nonelected national and state party officials, but her edge has been narrowing.
The elected are the party's 28 governors, 234 House members, 49 senators and assorted big-city mayors and state officeholders. Democrats in both camps say that for many, these superdelegates' decisions to endorse someone -- or stay uncommitted -- reflect their answer to the question: What is best for my political future?
The nonelected superdelegates are the more than 400 national and state party officers of the Democratic National Committee. While many lean to the candidate who would draw more votes in their states, Democrats say that for most the bigger question is this: Who has the best chance of winning the White House?
Among elected officials, Sen. Obama leads in endorsements from governors and senators. He is behind among House members by one, but both camps expect him to pull ahead unless he does badly in next Tuesday's Indiana and North Carolina primaries. If he doesn't stumble, enough elected Democrats are expected to back Sen. Obama after the last primaries June 3 to give him the delegate majority needed for nomination.
Many of them see Sen. Obama as more electable than Sen. Clinton. But even those who don't have been impressed by his grass-roots organizing and fund raising and the legions of new voters he has attracted, particularly younger and African-American voters.
The politicians -- especially Democrats with significant African-American populations or college campuses in their districts -- see benefit for themselves in these new voters. By contrast, many see Sen. Clinton's alienating some general-election voters.
A Democratic strategist to congressional candidates cites Sen. Clinton's high negative ratings in opinion polls. Politicians "all think Obama will stimulate African-American turnout, and they all know there's no way she gets independents or Republicans," says the strategist, who is unaligned in the presidential race.
Sen. Clinton still leads in endorsements from nonelected officials. Many have known her and former President Clinton since the couple's White House years, or worked for them then.
The Clinton campaign is counting on this group to be fertile ground to sow doubts about Sen. Obama's electability, citing his weaker showings in big states and among working-class whites, seniors and Roman Catholics.
The Obama camp late last week countered by emailing superdelegates a memo citing state polls to argue that either Democrat could beat Sen. John McCain, the likely Republican nominee, in the big states where Sen. Clinton beat Sen. Obama in the primaries, such as California and New York. But Sen. Obama, the memo contended, would "put new states in play."
His campaign also just announced a 50-state voter mobilization. That reflects another pitch to nonelected party officials: That Sen. Obama would work to build the party even in Republican "red" states, and has the money to do it, while Sen. Clinton focuses only on Democratic "blue" states and battlegrounds such as Ohio.
Interviews with party officials suggest this appeal has effectively exploited lingering resentments that the DNC, under President Clinton, abandoned the red states. "Obama has made it absolutely clear he's committed to the 50-state strategy, and the Clintons obviously aren't," says Nebraska party chairman Steve Achepohl, who endorsed Sen. Obama last week. "That's a major factor for all the party people in smaller states."
About 300 of the 795 superdelegates remain uncommitted; they don't have to endorse anyone until Aug. 27 at the Democrats' Denver convention. Party Chairman Howard Dean, among others, is urging them to go public after the primaries end.
Many have remained uncommitted either because they aren't sold on either candidate or, given the close race and each side's passions, they don't want to anger large blocs of voters. Also, House Democratic leaders have begun advising vulnerable Democrats against endorsing anyone.
In recent special elections in Mississippi and Louisiana, Republicans sought to tie Democrats to statements by Sen. Obama's pastor, the Rev. Jeremiah Wright Jr., whose sermons have been criticized as unpatriotic and racially charged.
"The ones that are squirming the most are a lot of these freshmen congressmen," says longtime California consultant Bill Carrick. A number were elected from Republican-leaning districts in 2006, when Democrats regained control of Congress. "All of them assume they're going to have pretty competitive campaigns in the fall, and they don't want to have to tell one group of their constituents that they're going with the other candidate."
When the year began, about 200 of the superdelegates had taken sides, most for Sen. Clinton. Her campaign, including Mr. Clinton, had quickly signed up Clinton-administration veterans, others on the DNC and elected officials in Arkansas and New York, so that she initially led Sen. Obama by more than 100.
But the Obama campaign correctly figured that she had gotten the easy pickings and that the rest were up for grabs. Once he began winning more states than she did, her endorsements slowed to a trickle, and her lead eroded to less than two dozen now.
Bob Mulholland, a longtime California party official, says he "absolutely" will remain uncommitted until after June 3, so voters speak first. Then the candidate with the most delegates "is going to be in very good shape to get the superdelegates."
Many superdelegates increasingly seem to share the view that ultimately they should support the candidate with the most pledged delegates. Almost certainly that will be Sen. Obama. "They argue that if the party insiders took this away from the winner of the voters' process, that could be disastrous for the party. And I agree with that," says Mr. Achepohl, the Nebraska Democratic chairman.
Clinton supporters privately contend the argument that party leaders should rubber-stamp the pledged-delegate winner reflects racial pressures. They complain that Obama backers are fanning talk of mutiny among Democrats' most loyal constituency -- black voters -- if Sen. Obama loses his bid to be the first African-American nominee of a major party after he had won the most pledged delegates. That could imperil Democrats' majority in Congress.
The Clinton side argues superdelegates should decide independently, as party rules intended, to guard against nominating an unelectable standard-bearer.
"Superdelegates must look to not one criterion but to the full panoply of factors that will help them assess who will be the party's strongest nominee in the general election," wrote 20 pro-Clinton fund-raisers last month to House Speaker Nancy Pelosi. They were protesting her pronouncements that superdelegates should ratify the pledged-delegates winner, and pointedly reminded her of their past contributions to congressional Democrats.
The letter angered Rep. Pelosi, but Clinton advisers say the shot across the bow was worth it.