WASHINGTON ― If there had been any doubts, President Barack Obama expunged them on Friday afternoon: The outgoing president wants his labor secretary, Thomas Perez, to succeed him as the top figure in the Democratic Party.

“Tom Perez has been, I believe, one of the best secretaries of labor in our history,” Obama said at his end-of-year press conference. This week, Perez challenged Rep. Keith Ellison (D-Minn.) in the race to chair the Democratic National Committee. Obama did not mention Ellison by name in his remarks.

For weeks, the Obama administration has been the principal holdout in a D.C.-based effort to unite the warring wings of the Democratic Party behind Ellison. The Minnesota liberal was the most prominent Capitol Hill supporter of Sen. Bernie Sanders (I-Vt.) during the presidential primary, and he has been embraced by establishment Clinton-backers including Senate Minority Leader Harry Reid (D-Nev.), his successor Chuck Schumer (D-N.Y.) and key labor leaders, including American Federation of Teachers President Randi Weingarten and American Federation of State, County and Municipal Employees President Lee Saunders.

But key figures from the Obama administration had chafed at the new alignment, with former Obama aide David Axelrod championing Perez in the press, following meetings between Perez and a host of administration figures. Obama erased any doubt about his views on Friday.

“If you look at his body of work on behalf of working people, what he’s pushed for in terms of making sure that workers get a fair deal, decent wages, better benefits, that their safety is protected on the job, he has been extraordinary,” Obama said.

The president stopped short of formally endorsing Perez, however ― a move that mirrors his positioning during the Democratic presidential primary. Though Obama made clear he supported Hillary Clinton’s bid for president in speeches and interviews, he held off on officially endorsing her until the party process had concluded. He appears to be following the same strategy in the DNC race.

“Now, others who have declared are also my friends, and are fine people as well, and the great thing is, I don’t have a vote in this,” Obama said. “So we’ll let the process unfold.”

Many leading Democrats in Washington are furious with the administration for intervening in a transition of power that they have been attempting to manage for weeks. Obama, they argue, has actively undermined party organization by diverting resources to his own organizations, after appointing a disastrous DNC chair in Rep. Debbie Wasserman Schultz (D-Fla.).

“The White House didn’t just let the DNC wither on the vine, they actively undermined it by steering money, resources, time and staff to [Organizing for Action],” one Senate Democratic aide told HuffPost. “It takes a lot of nerve for the White House, at the 11th hour, to meddle in race to head an organization they thwarted for eight years.”

Obama and Ellison have squared off over a host of issues over the years. Ellison called to curb the administration’s aggressive deportations of undocumented Americans, and opposed administration proposals to cut Social Security benefits as part of a (never-enacted) “Grand Bargain” with congressional Republicans. Ellison was an early opponent of Obama’s Trans-Pacific Partnership trade deal, arguing it would undermine American workers without providing adequate protections for foreign laborers.

Perez, who supported TPP, has been one of the most progressive members of the Obama administration. As Labor Secretary, he has pursued new regulations to expand the number of workers who qualify for overtime pay and require retirement account managers to manage investments in the best interests of their clients rather than seek out their own kickbacks. Both of those achievements will likely be unwound by the Trump administration before they can be implemented.