Even for a country like Pakistan, ravaged by terrorism for the last 14 years, the Taleban attack on the Army Public School in Peshawar that killed more than 140 - 132 of whom were children - is an act of unprecedented savagery. This is the most brutal attack on a school anywhere in recent years.
The extent of grief is palpable. The significance of this inglorious day - Dec 16 - was not missed. Pakistan lost half of the country, leading to the creation of Bangladesh, that day in 1971.
The Tehreek-e-Taleban Pakistan (TTP) claimed responsibility for the attack in retaliation for the North Waziristan operation launched by the Pakistan army in June this year. The group was also responsible for attempting to kill Malala Yousafzai, the recent Nobel Peace Prize winner, in 2012.
For now, the attack has brought in a rare display of unity in a sorely polarised country where most people acquiesce to extremist-driven violence.
Following the widespread public outrage, people hope that this attack may signal a decisive turn in Pakistan's reluctance in taking the menace of extremism head on.
Given the history of state responses to equally deadly attacks in the past, such a hope may be a little too optimistic.
It was telling that Prime Minister Nawaz Sharif, after huddling in an All-Parties Conference attended by the army chief, pledged no differentiation between the "good" and "bad" Taleban while eliminating terrorism from the country.
This was a stark admission of ambivalent state policy towards the Taleban - viewing it as consisting of "good" and "bad" components. Such ambivalence has created fertile ground for mounting militancy in Pakistan.
Mr Sharif disappointingly announced the setting up of a committee to draft a "plan of action" against terrorism to be submitted in seven days.
This is an astonishingly weak response from a state to an encroaching phenomenon that has claimed 50,000 lives.
The TTP emerged as a loose coalition of militant factions in support of Afghanistan's Taleban around 2007. Reflecting the widely held public resentment against the United States for its actions against Islamic countries, the TTP has increasingly turned its guns against Pakistan's state institutions.
Despite repeated warnings from the world community, Pakistan has been ambivalent about taking on these extremist forces, which were initially nurtured with Saudi and US money for fighting the Soviets during the 1980s. Weak civilian governments have shown reluctance to act decisively against them for the fear of alienating the military that incubates the "good Taleban" allegedly for use as proxies against India.
Pakistan's big enemy is the state of denial within. Its national narrative has yet to own up to the reasons of militancy and extremism. On television, news anchors and discussants conveniently blame extremist acts on "foreign hand" - more specifically the Indian intelligence organisations.
Pakistan is also trapped in its delusions of grandeur. Ambitious to be treated on a par with increasingly wealthy and powerful India, now courted by world powers, Pakistan is diverting limited resources and effort away from human and social development. Consequently, except for war-ravaged Afghanistan, Pakistan ranks lowest in South Asia in the Human Development Index, according to a recent United Nations report.
Absence of gainful opportunities for youth becomes the breeding ground for extremism and militancy.
Meanwhile, the government of Mr Sharif has done little to contain the Saudi-funded Taleban seminarians - perhaps because he is indebted to the Saudis for hosting him in style during his exile years.
Within the political sphere, some of Pakistan's political parties, especially those based on certain sects of Islam, have sympathy for these militants.
Given the backdrop, the present government, facing mounting challenges and feeling insecure, will be hesitant to take a sustained and effective action against militants.
The most likely action will come from the army, which has reacted strongly whenever its own institutions are targeted, like now. Yet, again the army will want unequivocal civilian backing in its campaign against militants, which may still take longer in the making.
It might be wishful thinking, but hard decisions need to be taken once and for all.
An effective investigative and judicial process needs to be instituted to provide a quick disposal of terror-related cases.
The government needs to immediately concentrate on reforming the curriculum to inculcate civic and universal human values among the growing population of youth. The state should control the mosque pulpit and seminaries. Education, especially at the tertiary levels, should be geared towards employability.
Instead of wasteful expenditures, the government must concentrate on creating job opportunities. The state needs to activate robust anti-terrorist machinery.
The international community should provide resources to Pakistan to support only its anti- terrorism, social sector and developmental goals.
Pakistan needs to understand that "your flag only flies as high abroad as it does inside", which was the case during three days of national mourning. To make it fly full mast, Pakistan needs to set its own house in order first.
The writer was Pakistan's High Commissioner to Singapore from 2004 to 2008 and is an adjunct professor at the Lee Kuan Yew School of Public Policy, National University of Singapore.