“I have never felt the anxiety I feel now,” said Sami Ghalib, a political analyst and former newspaper editor. “There was always geographical conflict, but now it is turning ideological. There are assassinations taking place everywhere. And at the helm, we have a leader who behaves like Saleh but doesn’t even have his political skills.”

Unlike his predecessor, Mr. Hadi is a virtual recluse who rarely speaks in public and has failed to offer a clear vision for addressing any of the crises afflicting the country. His fierce praise for the American drone-strike program, which is unpopular here, has further eroded his small base of public support. He is widely said to fear for his life and has appointed many family members and old allies to security positions.

Some progress has been made. A military campaign last year recaptured several southern towns from the jihadist militants who had controlled them for more than a year. But most of the fighters seem to have melted back into the population, and in the wake of the military’s withdrawal, large areas of the south remain a checkerboard of mysterious armed groups with no government presence.

Meanwhile, Al Qaeda’s Yemeni affiliate has adopted a new tactic: a ruthless campaign of assassinations that has left 74 military and intelligence officers dead since the start of last year, according to Interior Ministry officials. Almost all of the killings have been carried out by masked gunmen on motorcycles — often with pistols equipped with silencers — and only a few suspects have been arrested.

Mr. Hadi’s supporters point out that he inherited a fearsome set of challenges. He took office a year ago under the terms of a phased transition plan brokered by the Gulf Cooperation Council, a Saudi-led regional body, with the support of the United States and other Western powers. He was the consensus candidate inside Yemen largely because he lacked an independent power base and was therefore inoffensive to the tribal and military chiefs who wield real influence. His primary task was to undermine those chiefs, whose corrupt systems of patronage constitute one of the main obstacles to any real change.