In an e-mail message to staffers obtained by The Associated Press, Mike Henry said he was stepping down to allow campaign manager Maggie Williams to build her own staff. Williams replaced Patti Solis Doyle during the weekend. Solis Doyle had recruited Henry to join the campaign last year.
"Out of respect for Maggie and her new leadership team I thought it was the best thing to do," Henry wrote. "As someone who has managed campaigns, I share the unique understanding of the challenges that the campaign will face over the next several weeks. Our campaign needs to move quickly to build a new leadership team, support them and their decisions and make the necessary adjustments to achieve the winning outcome for which we have all worked so hard for over a year now."
It was unclear whether Henry was forced out.
His departure came amid the latest round of bad news for Clinton's campaign.
Obama continued to rack up wins - the latest in Virginia's presidential primary, one of three contests Tuesday - beating Clinton in the state by a 2-to-1 margin. He also was expected to prevail in contests in Maryland and the District of Columbia.
Henry was the campaign's main field architect and was best known for writing a memo last spring urging Clinton not to compete in Iowa, "our consistently weakest state." The memo was leaked to the media, which embarrassed Clinton as she was beginning to build an organization in Iowa.
Clinton placed third in Iowa, behind Obama and John Edwards, who has since left the race. Her campaign has struggled since then.
Guy Cecil, another top field strategist, was expected to succeed Henry.
