Before the April ceasefire, the U.S. had already bombed military targets on Kharg, including air defenses, a naval base and mine storage facilities, though it largely left oil facilities on the island intact.A ground invasion would be far riskier, according to some expert observers.“Trump would be gambling that the remaining Iranian leadership, faced with the loss of tens of billions in annual revenue, would capitulate,” Christian Emery, an associate professor specializing in U.S.-Iran relations at University College London, said in March.But “military success is by no means guaranteed,” he added, with the “real risk of it spiraling into a far more dangerous” situation.An oil facility on Kharg Island in 2017.Atta Kenare / AFP via Getty ImagesBecause most of Iran’s coastline is too shallow for supertankers, the country pumps almost all of its crude production through underwater pipelines to Kharg.Once used by Iran's monarchy to exile political prisoners, this rock is deceptively fertile on the ground. A short film by regime-controlled broadcaster Press TV last year showed groves of palm trees growing among freshwater springs, a rarity for Gulf islands.Archeological sites include 2,400-year-old wall carvings and rock-cut tombs, and there is an 18th-century fort built by the Dutch East India Company.Pipes leading downhill toward the Kharg Island jetty in Iran from the 17 million-barrel-capacity tank farm in 1971.Horst Faas / APIn the 1950s, the island was developed into the sprawling oil facility that exists today. It's also home to at least 8,000 residents, many of them oil workers.Access is restricted for non-residents, earning it the nickname "Forbidden Island," but satellite and aerial images show rows of oil storage tanks, flames gushing from flare stacks, a web of pipelines and vast piers that in peacetime allow supertankers to transport oil around the world — mostly to China.“Kharg Island is a lifeline for Iran’s economy,” Dania Thafer, executive director of the Gulf International Forum, a think tank based in Washington, D.C., said in March. Tehran would “likely escalate sharply” if the island is attacked, she said, intensifying strikes on U.S. forces and Gulf energy infrastructure.Trump himself has downplayed Iran's potential defenses. “I call it ‘the little oil island’ that sits there, so totally unprotected,” he said in March.He has had designs on it since at least 1988, when he told The Guardian newspaper that “I’d do a number on Kharg Island; I’d go in and take it,” referring at the time to a potential future conflict with Iran. Trump said in the interview that taking the island would be a way to pressure Iran.At the time Trump made the comments, marine traffic was being disrupted in the Persian Gulf. During the Iran-Iraq war in the 1980s, dozens of merchant vessels were attacked by both parties in what broadly became known as the “tanker war.”The USS Tripoli amphibious assault ship enters the Singapore Strait amid the U.S.-Israeli conflict with Iran as seen from Singapore on March 17.Edgar Su / ReutersSome analysts have said previously that seizing the island could give the U.S. leverage over Iran.“If the plan is to win a war against Iran, then taking Kharg Island should be one of the central missions of the conflict,” Francis A. Galgano, a former Army lieutenant colonel who is now a professor of military geography at Villanova University, said in March. “It provides the U.S. with enormous leverage in any negotiations and it’s a ‘stick’ to force the Iranians to stop attacking shipping.”Others are not so sure.One senior official from a Persian Gulf country, speaking on condition of anonymity to discuss these sensitive issues, warned in March that “Iran still has tools that it can make an occupation force by the U.S. still very risky."Others are less optimistic still.Kharg Island is less than 20 miles from the mainland, well within rocket, artillery and drone range, according to Emery at University College London. It is also hundreds of miles inside the Persian Gulf, meaning any U.S. force would take at least a day to reach it and “providing time for Iran to mine surrounding waters and prepare defenses,” he said.Even if the U.S. did capture the island, “holding the position would be extremely challenging, with resupply operations exposed to persistent drone, missile and artillery fire,” he said. Ultimately, he believes, it “would be an absolutely disastrous decision that would ensure the conflict lasted many months.”