When U.S. President Donald Trump tweeted, on May 10, that India and Pakistan had agreed to a cease-fire, the world breathed a sigh of relief. The two nuclear-armed neighbors had teetered perilously close to all-out war as they fired missiles and drone strikes at each other’s military installations and religious sites over the previous three days.

1972 — India and Pakistan sign a peace accord, renaming the ceasefire line in Kashmir as the Line of Control, a heavily fortified stretch of military outposts that divide the region between them. Both sides deploy more troops along the frontier, turning it into a heavily fortified stretch of military outposts.

The fact that India and Pakistan were able to agree to a ceasefire as escalations spiralled is reason for optimism. It shows that internal calculations and international pressure can pull the two parties back from the brink. However, the ceasefire represents an incredibly precarious peace. Can it be sustained?