The attack on the Cathedral of St Mark in Cairo on Sunday was in one respect a watershed: never before has what is essentially the headquarters of the Coptic Orthodox Church been attacked in this manner.
But in most other ways, the sentiment many Egyptians feel is one of dazed, if horrified, familiarity. There simply have been too many such attacks in the recent past.
It is depressing enough that this sectarian incident came on the heels of another one: the cathedral was attacked after it hosted a funeral march for the five Christian victims of clashes between two families in Al Khusus, a small town north of Cairo.
But perhaps most distressing was the fact that as young men rallied to the cathedral to defend it, they displayed the tattooed crosses on their wrists to prove they were Christians to be allowed in. It was a heartbreaking sign of the social fragmentation that is taking place in this country.
Among the many reasons for the uprising against Hosni Mubarak's rule that took place in Egypt in 2011, one immediate precursor was the bombing of Al Qiddissin church in Alexandria that took place during the New Year's Eve service. The attack, which claimed 21 lives, unleashed a torrent of sympathy and prompted a rare self-critical look at sectarian relations.
What was remarkable about this outburst is that it bucked a reflex by both the government and much of society to claim that such sectarian attacks were aberrations, or "alien to Egyptian society". That attack on the church was the worst (as opposed to sectarian clash) in a long time - perhaps since Copts were regularly targeted by the Islamist insurgency waged by the Gamaa Islamiya in Upper Egypt in the early 1990s.
Perhaps more importantly, it followed - by only a month - what was widely seen at the time as the worst case of sectarian rioting pitting Copts against the state itself. In late November 2010, angry Christians in the Cairo district of Omraneya battled riot police after reports spread that local authorities would prevent work to expand a local church. One young Christian was killed in the battle with the police.
But even that incident paled compared to the October 2011 Maspero incident, when military troops and citizens attacked a mostly Christian group of protesters outside of Egyptian television headquarters. Then at least 28 were killed - some by being run over by armoured personnel carriers - and a Muslim mob even attempted to storm the hospital where the mostly Christian victims had been taken.
Between the Al Qiddissin bombing and the Maspero massacre, no one could pretend anymore that sectarianism in Egypt is simply a problem emanating from traditional family feuds that takes place in the countryside, or the pernicious influence of a few radical fundamentalists. It is a problem that the state is directly involved in, whether it is through its long-standing approach to sectarian incidents as chiefly a security problem, or its lack of diligence in preventing tensions and investigating sectarian violence when it takes place.
Eyewitnesses at St Marks' Cathedral all relate that police simply stood by as stones and Molotov cocktails were thrown at the compound. Others even claim that the security services might have been involved, with thugs seen trucked in to take part in the attack.
As is often the case on such occasions, it is hard to discern what really happened. President Mohammed Morsi has promised an investigation. But his own foreign policy adviser (in an English-language statement on his Facebook page, suggesting that the presidency considers sectarian violence a foreign policy issue) appears to have jumped the gun and blamed the Coptic protesters, who were chanting anti-Brotherhood slogans, for starting the fighting.
In public statements and in parliament, Islamists have suggested the Coptic Church bears part of the blame for the violence (those defending the church, of course, were armed and battled with the assailants) and spoken about "Coptic militias" — striking a rather deaf tone in the context of deep anguish about the attack among many Egyptians, Coptic and Muslim, and the clear imbalance of power between the two communities. The government has also failed to comment thus far on the police's inaction.
Such murkiness appears cultivated. Investigations do not carry much weight when the results of all previous investigations announced by the government have either been buried or ignored.
For instance, allegations still circulate that the Alexandria church bombing in 2011 may have been ordered by Mubarak's last interior minister. How the Maspero massacre started remains an official mystery, and neither the military nor state media have been held accountable for their role in the violence.
To blame the Morsi administration for how the police acted in this latest case may be premature - there have been plenty of signs that the police are often unwilling to do their duty in recent months. But to be credible, Mr Morsi has to do more than merely utter platitudes about his grief at seeing sectarian violence. He must take them to task for their behaviour on Sunday, and not remain silent when some of his colleagues attempt to blame the victims.
As an Islamist president, he will be doubly scrutinised for how this is handled. His credibility on sectarian relations is already low after he declined to attend the coronation of the new Coptic pope and pushing the adoption of a new constitution without the endorsement of the Christian community. He must do better.
Issandr El Amrani is an independent journalist based in Cairo who blogs at arabist.net
On Twitter: @arabist