But the main players have grown so wary of leaving Mr. Trump’s side that it has become hard to organize meetings of senior officials without him, to thrash through policies or hiring choices, slowing up an already fitful process. Meanwhile, the conflicting sides have been waging proxy battles through friendly news media outlets.

While alliances have been fluid in this White House, Mr. Kushner is joined by more centrist-minded advisers including not only his wife, Ivanka Trump, who now has her own West Wing office, but also Gary Cohn, the president’s national economics adviser, and Dina Powell, a deputy national security adviser, both veterans of Goldman Sachs.

Mr. Bannon’s closest ally is Stephen Miller, the president’s senior adviser for policy and the author of orders to temporarily ban visitors from certain predominantly Muslim countries. And although they were once at odds and still come from vastly different vantage points, Mr. Bannon has also maintained an alliance of convenience lately with Reince Priebus, the chief of staff closely associated with the Republican Party establishment.

In recent weeks, as Mr. Bannon has felt increasingly frustrated, Mr. Priebus has several times bolstered the chief strategist in discussions with the president, according to people with direct knowledge of the talks. In turn, Mr. Bannon has gone out of his way to praise his onetime rival’s performance.

Mr. Kushner and the others are said to be especially concerned about the geyser of bad headlines that have marked the president’s first two and a half months in office. They have resisted many of the more polarizing policy initiatives favored by Mr. Bannon’s side, including the travel ban and rollbacks of environmental regulation and of protections for transgender students, arguing that they undercut Mr. Trump’s election night pledge to be a president for all Americans.

On foreign policy, Mr. Kushner is more inclined toward intervention in the Middle East while Mr. Bannon would prefer that the United States remain as uncommitted as possible. Even as the president signaled this week that he might respond militarily to the chemical attack on civilians in Syria, Mr. Bannon has argued that American interests are better served by not getting drawn any further into the quagmire of a civil war.