Even as coup rumors circulated that October, American officials had warned General Hamdan that he would face “specific consequences” if he seized power, a former senior U.S. official said. But after the coup, Molly Phee, the department’s top Africa policy official, led American diplomats in trying to work with the generals rather than enter into confrontation with them.

The U.S. official declined to specify the proposed sanctions against General Hamdan but said they broadly targeted his personal wealth, much of it held in the United Arab Emirates — a war chest that experts say was critical to building up a military force that has been unleashed in the current fighting.

The United States did not punish General Hamdan with sanctions after the coup — or even after he visited Moscow, on the first day of Russia’s assault on Ukraine last year, to glad-hand senior Kremlin officials.

Pressure to punish the generals came from senior members of Congress. Senator Chris Coons, a Delaware Democrat on the Senate Foreign Relations Committee’s subcommittee on African affairs, co-wrote in a Foreign Policy article in February 2022 that the Biden administration should impose a “comprehensive set of sanctions on the coup leaders and their networks” to weaken their grip.

Speaking to reporters during a trip to East Africa with Secretary of State Antony J. Blinken in November 2021, one senior State Department official said the generals had indicated that they were willing to again share power with civilians. The official, who insisted on anonymity to talk about the negotiations, said that withholding aid might not do enough to pressure the generals, and so the administration had appealed to their sense of an honorable personal legacy, among other things.