World powers have often been known to intervene, overtly and covertly, to overthrow other countries' governments, install pliant regimes, and then prop up those regimes, even with military action. But, more often than not, what seems like a good idea in the short term often brings about disastrous unintended consequences, with intervention causing countries to dissolve into conflict and intervening powers emerging as targets of violence. That sequence is starkly apparent today as countries that have meddled in the Middle East face a surge in terrorist attacks.

Last month, Salman Ramadan Abedi — a 22-year-old British-born son of Libyan immigrants — carried out a suicide bombing at the concert of the American pop star Ariana Grande in Manchester, England. The bombing — the worst terrorist attack in the United Kingdom in more than a decade — can be described only as blowback from the activities of the U.K. and its allies in Libya, where external intervention has given rise to a battle-worn terrorist haven.

The U.K. has not just actively aided jihadis in Libya; it encouraged foreign fighters, including British Libyans, to get involved in the NATO-led operation that toppled Col. Moammar Gadhafi's regime in 2011. Among those fighters were Abedi's father, a longtime member of the al-Qaida-linked Libyan Islamic Fighting Group, whose functionaries were imprisoned or forced into exile during Gadhafi's rule. The elder Abedi returned to Libya six years ago to fight alongside a new Western-backed Islamist militia known as the Tripoli Brigade. His son had recently returned from a visit to Libya when he carried out the Manchester Arena attack.