Yet another attack on Pakistan’s minority Shiite sect – this time in Karachi on Sunday night, killing at least 45 people – further exposes the failure of the government to rein in a growing wave of sectarian violence. Sunni militants killed more than 400 Shiites in targeted attacks in Pakistan in 2012 – the largest annual total – according to Human Rights Watch. An attack on a billiard hall in southwest Baluchistan province in January killed over 90 Shiites . Five weeks later a blast in a Shiite-dominated area of Quetta killed a further 84 people. In response, Pakistan has put Baluchistan under direct government control in an attempt to curtail the action of the al-Qaeda linked militant groups that have operated freely there. The government also has clamped down on Lashkar-e-Jhangvi, the militant group that claimed responsibility for January’s attack and is widely believed to be behind the latest bomb attacks on Abbas Town, a Karachi suburb. Police arrested Malik ...