Ho Chi Minh City was blanketed in red banners on Thursday that read “Long Live the Glorious Communist Party of Vietnam,” 40 years after northern forces seized control of the country and America walked away from a divisive and bloody war that remains a painful sore. Thousands of Vietnamese watched a parade through the streets of what was once Saigon. Across an ocean, U.S. veterans remember April 30, 1975 as the day North Vietnamese tanks rolled into the city, and the U.S. lost a war.