Iran’s nuclear-armed neighbour Pakistan has invoked its mutual defence pact with Saudi Arabia in response to Tehran’s missile and drone attacks on the kingdom, in what analysts have described as a key test of Islamabad’s emerging role in the Middle East’s security architecture. A gently worded warning to the Islamic Republic, delivered by Ishaq Dar, Pakistan’s deputy prime minister and foreign minister, has established Islamabad as a go-between to manage the escalation. Briefing the Senate on...