Mr. Ajami is a senior fellow at Stanford University's Hoover Institution and co-chairman of Hoover's working group on Islamism and the International Order.

On the face of it, the similarities of the undoing of the terrible regimes of Saddam Hussein and Moammar Gadhafi are striking. The spectacles of joy in Tripoli today recall the delirious scenes in Baghdad's Firdos Square in 2003—the statues pulled down, the palaces of faux grandeur and kitsch ransacked by people awakening to their own sense of violation and power, the man at the helm who had been full of might and bravado making a run for it, exposed as a paranoid and pretender, living in fear of his day of reckoning.

In neither case had the people of these two tormented societies secured their liberty on their own. In Baghdad, the Baathist reign of terror would have lasted indefinitely had George W. Bush not pushed it into its grave. There had been no sign of organized resistance in that terrified land, not since the end of the 1991 Gulf War and the slaughter that quelled the Shiite uprising.

Libya offered its own mix of native resistance and foreign help. A people who had been in the grip of a long nightmare saw the Arab Spring blossom around them. On their western border, the Tunisian kleptocracy had fallen and the rapacious ruler and his children and in-laws had scurried out of the country. Ruler and ruled in Libya saw themselves in the Tunisian struggle, for Gadhafi had been an ally of the Tunisian strongman.

But it was Egypt, the big country on Libya's eastern frontier, that shook the Libyan tyranny...