FDR was reflexively anti-imperialist; in any event, he was too busy fighting the Great Depression and fascism to spend much time with Latin America. He opted for the Good Neighbor Policy, and the nature of our relationship with the rest of the hemisphere changed for good, at least until now.
Most of our actions that smacked of imperialism during the Cold War were done purely in the name of fighting communism; in other words, they were motivated by ideology, not material self-interest. Jimmy Carter even gave back the Panama Canal. After an unsuccessful attempt to overthrow the regime in Cuba, we promised not to invade, and we kept our promise. We cemented our relationship with our immediate neighbors by signing the NAFTA agreement. A new era had begun.