Nearly five years after the last American troops left Afghanistan, al-Qaeda is again finding both sanctuary in the country and an audience far beyond it. A new report from Europol warns that jihadism remained Europe’s most widespread form of terrorism in 2025, accounting for 24 of the 45 terrorist attacks reported by European Union member states and 347 terrorism-related arrests. More ominously, the report finds that al-Qaeda is exploiting the war in Gaza to regain influence and incite attacks against Western and Jewish targets. The group Al-Qaeda in the Arabian Peninsula, or AQAP, has been particularly aggressive. Europol reports that...