By Mike Manzoni

As Sen. Barack Obama (D-Ill.) relished considerable momentum from his four-state primary sweep last weekend and comfortable wins Tuesday in the Virginia, Maryland and Washington, D.C., primaries, his rival, Sen. Hillary Clinton (D-N.Y.), began rallying Texas Democrats at a stump speech Tuesday night in El Paso, only hours after her deputy campaign manager became the second member of her senior staff to resign this week

Deputy campaign manager Mike Henry’s departure, first reported by Chris Cillizza on The Fix, a Washington Post politics blog, came two days after campaign manager Patti Solis Doyle stepped down after Sen. Clinton’s string of disappointing finishes.

“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,” Henry wrote in an e-mail to staff obtained by Cillizza.

After eight consecutive victories, Obama took the lead in pledged delegates, while Clinton, still holding the majority of super-delegates-public officials and party activists not tied to a candidate-is now pinning her hopes for the nomination on big wins in Texas and Ohio on March 4.

Obama’s wins in the so-called Potomac primaries were not much of a surprise to the Clinton camp who was aware of the dichotomy of mid-Atlantic voter demographics-blue-collar blacks and affluent whites-that were likely to flock to Sen. Obama, and did. But the margin of victory was much larger than what the Obama campaign expected.

In Virginia, with 99 percent of precincts reporting, Obama took nearly 64 percent of the vote, with Clinton only getting 35 percent. In the Washington, D.C. primary, Obama took 75 percent, with 97 percent of precinct reporting.

Maryland’s polls were held open for an extra 90 minutes by a judge due to poor weather conditions, and Obama took 61 percent of that vote, with 50 percent of precincts reporting.

Following the slew of losses Saturday, Clinton replaced campaign manager Patti Solis Doyle with longtime-adviser and former chief-of-staff Maggie Williams. The move came after she lost to Obama Saturday in Louisiana, Nebraska, Washington State, Maine and the U.S. Virgin Islands.

Doyle had assured competitive online fundraising, but she was never able to build the online cash bank like the Obama campaign has, who last week boasted a record $5 million in a single day of contributions, as revelations surfaced that Clinton had to lend her own campaign nearly that amount.

There were also indications that Sen. Clinton was concerned with ground organization, especially in states such as Maine, where she had hoped to win considering the state’s population of low-income Democrats who had voted for her in other contests.

Sen. Clinton, speaking from Maryland on Monday, said her loss in Louisiana was due to the state’s African-American electorate-a voting bloc that has favored Obama’s candidacy.

In a statement, Sen. Clinton said she was “enormously grateful for [Doyle’s] friendship and outstanding work,” and said that she “look[s] forward to her continued advice in the months ahead.”

Her camp maintains the switch was Doyle’s choice, but aides close to the camp say it has been coming since her unexpected loss in the Iowa caucuses last month, after which Williams began to take on a more dominant role in the campaign.

Pundits point to the less than satisfactory online fundraising efforts as the cause for Doyle’s stepping down. Henry’s departure comes after Sen. Obama surpassed Sen. Clinton in the pledged delegate count for the first time in the campaign.

But Henry was not the only staffer to leave Tuesday night. Two key internet staffers, Kevin Thurman and Crystal Patterson, left the campaign as well, according to a post from Greg Sargent, a reporter for TalkingPointsMemo.com, a liberal blog.

“Kevin and Crystal have been valued members of our team and we are grateful to them for their contribution to the campaign,” a Clinton staffer wrote in a statement to Sargent.

Obama delivered his victory speech to a roaring crowd in Madison, Wis. Tuesday night. “This movement won’t stop until there’s change in Washington,” he said. “And tonight, we’re on our way.”