But at a time when Afghan forces and officials are supposed to be running the war, and eight months after the official end of the NATO combat mission in Afghanistan, General Campbell’s prominent role is also being widely taken as a sign that the fight against the Taliban is not going well.

“Everyone knows who the minister of defense is in Afghanistan now, and it is not Masoom Stanekzai,” said one Western diplomat, naming the Afghan official whose nomination as defense minister was rejected by the Parliament but who was kept on as the acting minister. “The American combat role may be over, but you still have an American general running the war.”

Afghan officials who have worked closely with General Campbell, and who generally approve of his authority, say it has resulted from a mixture of the general’s take-charge personality and the dire situation that Afghanistan’s military leaders have found themselves in.

Casualties among Afghan troops have increased by 50 percent in the first six months of this year, compared with the same period in 2014 — and 2014 was already a huge increase over 2013. Taliban insurgents have opened new fronts in northern Afghanistan, and at times have been on the verge of overrunning the northern city of Kunduz. And the Afghan military has struggled to meet its recruitment goals, facing the prospect that its security forces may actually shrink in size this year.

Worst has been the recent situation in the southern province of Helmand, where on Aug. 26 the strategic district of Musa Qala fell to Taliban insurgents, who are on the verge of carving out a major territorial bastion in the area.