Idayat Hassan, head of the Centre for Democracy and Development think tank, said security was now front and center of the public's concerns.
"There is growing pressure from Nigerians across all walks of life on the need to address the insecurity plaguing the country," he said.
"The problem currently is nowhere is safe in the country -- and nobody, irrespective of class or position in life, is safe."
One of Buhari's big campaign promises in the last presidential election was to end insecurity -- and the relentless violence has left him politically exposed.
"Most of us have been supporters of Buhari because he is a general," said a member of the ruling party, Chief Frank Kokori, a former labor leader and rights activist.
"We feel he is negligent (with) the security of the country, that is obvious, and he has to wake up because he has squandered his goodwill."
A security source based in the northeast and who asked to remain anonymous, said "Buhari is in an unenviable position."
"Naturally he is to take responsibility for any security failures as the head of government, but the truth is that he is helpless."
Despite hefty investments in the security apparatus, the situation has "continued to deteriorate," he said.
Presidential elections are due to take place next February for a successor to Buhari. The former army general, first elected in 2015 and reelected in 2019, is scheduled to step down after two terms.
Opposition lawmakers threw down the gauntlet last month, threatening to impeach Buhari if he failed to stem the violence.
But the announcement is widely seen as an empty threat, given the ruling party's parliamentary majority.
Udo Jude Ilo, analyst and consultant with Thoughts and Mace Advisory, said the government had manifestly failed on the security issue.
He pointed to the holdup in March of a recently-inaugurated high-speed passenger train between Abuja and the northern city of Kaduna.
Eight people were killed, 26 were wounded and an unknown number were taken hostage.
"No-one was fired," Ilo said. "The service chiefs are still there. It is unbelievable."