Ranjit Singh's Khalsa deterred the British; without him it tore the empire apart

From 1799, when Maharaja Ranjit Singh captured Lahore, he welded the warring Sikh misls into the Sikh Empire and — uniquely among Indian powers — kept the British East India Company at bay behind a Sutlej river boundary. His instrument was a modernised army. Where he had found 'a mass of horsemen, brave indeed, but ignorant of war as an art,' he left, by one contemporary account, some fifty thousand disciplined soldiers, as many militia, and more than three hundred field guns.

That defence rested entirely on one man. Ranjit Singh died in June 1839, aged fifty-nine. After him the succession collapsed: Kharak Singh and Nau Nihal Singh both died within a year, Sher Singh was assassinated in 1843, and a child, Duleep Singh, was left on the throne. As the historian Cunningham put it, once 'his own commanding genius was no more, the vital spirit of his race began to consume itself in domestic contentions.'

Real power passed to the army's regimental committees (panchayats), which appointed and deposed rulers and even condemned a minister to death as 'a traitor to the commonwealth.' The sovereign, restless army then drove the state into war with the Company — the soldiers gathering round Ranjit Singh's tomb to vow fidelity to the Khalsa. The First (1845–46) and Second (1848–49) Anglo-Sikh Wars followed, and the second ended in the fall of the empire and the annexation of the Punjab in 1849.

The defence built to keep the British out became the instrument that let them in. Ranjit Singh had built a formidable military against the external threat, but no political institution to control that military once he was gone; loyalty ran to the man and to the Khalsa, not to an office or a succession rule.