The shakeup comes a week after McCain fired more than 50 staffers in the wake of a funding crunch. McCain raised just $11 million in the second quarter, less than GOP opponents Mitt Romney and Rudy Giuliani, but has burned through more cash than most of the other candidates in the field. In a conference call last week, Nelson and Weaver confirmed that McCain has only $2 million in the bank–a shockingly low number for a man who was once the presumed frontrunner for the GOP nomination.

But money hasn’t been McCain’s only problem. While the official statement from the McCain campaign Tuesday morning says Nelson and Weaver both resigned, it’s unclear if the departures were as amicable as suggested. Long before McCain’s financial difficulties, there were significant internal disputes over the direction and leadership of the campaign. Even McCain’s most loyal supporters were critical of what was a top-heavy organization in which people struggled to figure out who was boss. “It wasn’t clear who was in charge,” says one longtime McCain supporter, who declined to be named while discussing internal campaign strategy. “There were two, sometimes three or four, people playing the role of decision-maker and they were saying different things. You never knew who to listen to.”

Last week’s disappointing financials only heightened the pressure–and the divisions. A source close to the campaign tells Newsweek that McCain made clear that he wanted a change in direction, namely in running a more streamlined campaign. Nelson, who announced last week that he would work without a salary, has acknowledged that the campaign has operated until recently on the idea that they could raise $100 million this year. Last week, Nelson admitted that goal was misguided. While many McCain loyalists blamed Nelson for the shoddy fund-raising and out-of-control spending, he pointed fingers elsewhere, complaining he wasn’t given the full authority a campaign manager should have. “Ultimately, it’s the candidate’s fault,” admits one McCain loyalist. “It’s up to the candidate to set authority.”

Nelson and McCain weren’t personally close. Nelson, who previously worked for George W. Bush’s presidential campaigns, was recruited to the McCain campaign by Weaver. Sources say that Nelson previously offered his resignation earlier this year, after McCain failed to raise as much as his opponents in the first-quarter. It’s unclear exactly what happened between McCain and Nelson this time around. The campaign says Nelson resigned, but one Republican aligned with McCain says Nelson was “pushed out” over disagreements about how the campaign should move forward. Nelson’s departure, in turn, prompted Weaver to tender his resignation, say two McCain sources. Some reports had suggested that Salter–a longtime aide and author who has collaborated with McCain on “Why Courage Matters,” “Faith of Our Fathers” and “Worth the Fighting For,” had quit because of Weaver’s resignation. But Brian Jones, a McCain spokesman, says Salter will continue to advise McCain on “communications strategy and speechwriting” without pay.

While Nelson’s departure perhaps could have been predicted, McCain’s split with Weaver is surprising. Weaver has served as McCain’s Karl Rove, a consultant who has guided the senator through every tough political spot in recent years. He played a key role in negotiating a truce between Bush and McCain after the 2000 campaign. Weaver has been a ubiquitous presence on the campaign trail, traveling alongside McCain on nearly every political stop this year. But Weaver and McCain are also personally close friends. Both are cancer survivors–McCain had a cancerous growth removed from his face in 2000; Weaver battled leukemia.

Many McCain staffers and supporters were shocked by Tuesday’s developments. Some learned of the news as many reporters did: through a press release. “I don’t know what to think,” one McCain consultant told Newsweek. “I’m speechless.” The campaign has organized a series of meetings beginning this week and lasting through the weekend. Staffers and donors are expected to talk about their goals moving forward. For the loyalists left on the Straight Talk Express, the road to the nomination is getting longer by the day.