A recent view of downtown Havana. (Photo: Alexandre Meneghini/Reuters)For nearly 50 years, the United States tried various ways to end the Castro regime that rules Cuba. The disastrous 1961 Bay of Pigs invasion led to the convoluted scenarios laid out in “Operation Mongoose,” including plots to poison Fidel with a cigar, or a wet suit, or hiring organized crime figures to kill him. Later, the crippling U.S. economic embargo aimed to convince the island’s population to rise up and overthrow the Soviet ally just 90 miles off Florida’s shores.Both the use of force and economic pressure failed to bring about the desired result — while Castro boasted of surviving CIA hit jobs and blamed poor living conditions in socialist Cuba on the U.S. The bearded revolutionary outlasted U.S. president after U.S. president, and his government even survived the collapse of the Soviet Union, which deprived Havana of aid from Moscow. The end of the Cold War also set the stage for American allies, like Mexico, Canada and France, to carve out lucrative niches in Cuba’s tourism industry, leaving the United States isolated.When Pres. Barack Obama arrives in Havana on Sunday, it will be at the head of what amounts to a different kind of U.S. invasion. There will be air power: Airlines clamoring to be able to run direct flights to Cuba. There will be naval power: Cruise lines launching routes to Cuba. Marriott, looking to become the largest hotel chain in the world through a merger with Starwood, wants to establish a beachhead. And the president has potentially enlisted tens of thousands of infantry by recently loosening restrictions on Americans traveling to Cuba to such an extent that, while a ban on simple tourism remains on the books, it’s easy, in practice, to travel there to take in the sights.Slideshow: Alejandro Ernesto’s wide lens on Cuba >>>“Our central premise,” Obama told Yahoo News in an interview in December, is that if “they are suddenly exposed to the world, opened to America and our information and our culture and our visitors and our businesses, invariably they’re going to change.”The president will arrive in Cuba on Sunday evening with first lady Michelle Obama and their daughters, Malia and Sasha, for a whirlwind visit — a little less than 48 hours in Havana.“I look forward to being the first U.S. president to visit Cuba in nearly 90 years — without a battleship accompanying me,” Obama said recently, referring to Calvin Coolidge’s 1928 trip aboard the USS Texas.