The Afghan president’s options are limited, however, having publicly vowed in a recent speech not to rescind the name change out of respect for Mr. Rabbani’s memory. His own government includes Rabbani allies in powerful positions.

Burhanuddin Rabbani was the leader of the Jamiat-i-Islami party, an ethnic Tajik-centered group that fought against the Taliban, against the Soviets and later against other factions during the civil war in the 1990s. Human Rights Watch said in a 2005 report that he should be investigated for atrocities committed, “including intentional killing of civilians, beating of civilians, abductions based on ethnicity, looting and forced labor.”

Mr. Rabbani had also briefly served as president of Afghanistan after the fall of the Taliban, and peacefully handed over power to Mr. Karzai in 2001. Pashtuns, mostly from the south and east, are the most numerous ethnic group in Afghanistan, and as a Pashtun, Mr. Karzai was seen as a less divisive figure than a northerner like Mr. Rabbani would be. Many of the Taliban are Pashtuns, as well.

Mr. Karzai later appointed Mr. Rabbani as head of the High Peace Council, a body charged with seeking reconciliation with the Taliban — apparently to allay fears by northerners of a peace deal between Pashtuns that would leave them out. Last year, a man posing as a Taliban peace emissary turned out to be a suicide bomber with explosives in his turban, and he killed Mr. Rabbani.

To commemorate the Sept. 21 anniversary of Mr. Rabbani’s death, by presidential decree a major street in Kabul and the airport in Kandahar were named after the slain Tajik leader, and the Kabul Education University was re-christened Rabbani University.

The protests began immediately. Like so much here, they had a clear ethnic coloration, with Pashtun and Hazara students in the forefront, and their opponents — many of them not students — mostly Tajiks.

“Rabbani deserves this,” said Sayid Bahramudin, a Tajik from Baghlan, who said he was a student at “Kabul Education University,” momentarily forgetting the new name he had come to the street to defend. “He sacrificed for peace to bring peace.” The protesters, he said, “are all outsiders and terrorists.”