All recognize that Mrs. Clinton’s political operation could dominate the Democratic Party for the next decade, controlling the flow of commissions, consulting work and political appointments. But the marriage between the two camps — based to a large degree on mutual interest, if not love — now appears more uneasy than at any time since Mr. Obama asked Mrs. Clinton to serve in his administration after the 2008 election.

“It is ‘The Dream Team,’ but only five can start,” said John Morgan, a Florida lawyer who has raised money for Mr. Obama and hosted fund-raisers with former President Bill Clinton. “Who do you put at guard? Jordan, LeBron, Kobe, Magic, Bird, Derrick Rose? That is where it is.”

The list of Obama veterans now working in “Clinton World” includes the New York-based pollster Joel Benenson, whom Mrs. Clinton has settled on as chief strategist over several pollsters with long Clinton ties. A consulting firm founded by two Obama voter-turnout specialists, Mitch Stewart and Jeremy Bird, is being paid $20,000 a month by Ready for Hillary, a super PAC focused on organizing grass-roots Clinton supporters. Jim Margolis, whose firm handled lucrative media-buying contracts for Mr. Obama’s campaigns, will also advise Mrs. Clinton, whose campaign will probably raise and spend over a billion dollars in the next two years.

But Mr. Brock’s path to the Clinton inner circle is perhaps the most convoluted. Once a conservative journalist whose reporting on President Clinton prompted Paula Jones’s 1994 sexual harassment lawsuit against him, Mr. Brock has since emerged as a prominent liberal organizer and one of Mrs. Clinton’s chief defenders.

With the tacit blessing of both Clintons, Mr. Brock has maneuvered his $28 million network of media-monitoring and opposition research organizations into the center of the emerging Clinton effort, establishing a new project, Correct the Record, that has defended Mrs. Clinton in the news media and even issued daily emails explaining her positions.