The murder of Punjab governor Salmaan Taseer by his own guard has prompted an ever growing witch-hunt, driven by religious groups but controlled by no one. The threat of this uncontested vigilantism posing as Islamic empowerment should be taken as seriously as the Taliban.

There was a moment last weekend that juxtaposed beautifully with the latest crisis faced by Pakistan. As hundreds of thousands – Islamists and Marxists, centrists and otherwise apolitical working men and women – marched for democratic regime change in Egypt, 40,000 mostly men marched in Pakistan's heartland city of Lahore to protest against changes to the country's controversial blasphemy law regime. Protesters in Lahore threatened to cause greater anarchy if the blasphemy laws were changed – threats reminiscent of the Pakistan Taliban.

It is important to note that, as an instrument for protecting the honour of Islam, Pakistan's blasphemy laws have been an abject failure. As rights groups point out, the laws are vaguely defined and do not require accusers to prove criminal intent. Police rarely investigate before arresting alleged blasphemers. Taseer's murderer may say he killed him for committing blasphemy, but there is no evidence he ever did anything of the sort. Taseer's only crime was to highlight the severe failings of the blasphemy laws, a point lost on many who endorsed his murder.

"If a campaign were to be carried out on all the electronic media explaining exactly what the blasphemy laws are, the fact that vigilantes have murdered other people due to political, economic or other rivalries and motives, people would not favour it," says veteran journalist and human rights campaigner Beena Sarwar.

Since the current laws made defiling the Qur'an and defaming the prophet crimes punishable respectively by life imprisonment and death in 1986, anywhere between 300 and 3,000 people have been accused of blasphemy. Of these, roughly 50% belong to religious minorities, a group that constitutes only 3% of Pakistan's 180 million population.

But the blasphemy laws do not just target religious minorities and the poor. The slain Taseer, a wealthy businessman and key ally of President Asif Zardari is testament to that. But even Muslims are not safe from the witch-hunt. During a visit to a village in the Punjab late last year, I was told that local Sufi Muslims had charged "a young Wahhabi" with blasphemy for arguing that Prophet Muhammad was a human being and that prayers should not be directed to him or venerated saints but only Allah.

Last Saturday a magistrate remanded a 17-year-old boy on charges of blasphemy after he allegedly wrote insulting comments about the Prophet during an exam more than eight months ago. Most disturbing, the charges were brought by the intermediate board of education in Karachi. The board noted that the boy confessed to the "unpardonable sin" and blamed it on frustration over inability to answer an exam question and the influence of a discussion about Islam he had with some cousins from Norway.

In a society where the law and order system is already fragile and amenable to vigilantism, the blasphemy law has opened up a Pandora's box of opportunities for people to take the law into their own hands, or force fearful police and courts to provide a rubber stamp to their vendettas. None of Pakistan's major politicians or its powerful army chief, not traditionally averse to making public statements on matters of national interest, has condemned Taseer's murder or the misuse of the blasphemy laws.

Political parties were glaringly absent from public prayers organised for the slain Taseer over the weekend. In response to a request to attend one of them, Senator Abdul Rahim Khan Mandokhel from Balochistan said, "he [Taseer] met his fate. This is our religion. You have to accept it or leave Pakistan." In an open letter, a broad coalition of citizens called the Citizens for Democracy condemned the remarks and urged the president of the senate to take disciplinary measures against Mandokhel if he did not offer a public apology. Others have called on the courts and police to charge people who have publicly called for victims of the blasphemy laws or advocates for their reform to be murdered.

It is arguable that even more dangerous are those like Mumtaz Qadri, Taseer's murderer, who act out of a genuine belief that, armed just with God's command, any citizen has the right to commit murder based on rumour and slander.

On Monday, Pakistan's prime minister Yusuf Raza Gilani reiterated his government's refusal to amend the blasphemy laws, noting proudly that it was his predecessor Zulfiqar Ali Bhutto who "introduced this law in Pakistan". True, Gilani's government is besieged and in no position to pick a losing battle. But if more Pakistanis do not wage a war for sanity all of us will lose.