One hundred days after the Iran war began, the Islamic Republic appears stable. But beneath the surface, economic strain, social unrest and growing repression point to deeper instability.

Both sides say the ceasefire between the US and Iran remains in place. But that line feels ever less grounded in reality.

The war in Iran reaches its 100-day mark on June 7, with US involvement, shifting alliances and escalating regional tensions reshaping the Middle East and raising questions about…