After World War II, the US government got into the regime change business in a big way. It was easier than invading countries and deposing their undesirable governments. From Stephen Kinzer, reviewing Covert Regime Change: America’s Secret Cold War by Lindsey A. O’Rourke at fff.org:
Covert Regime Change: America’s Secret Cold War by Lindsey A. O’Rourke (Cornell University Press, 2018); 330 pages.
For most of history, seizing another country or territory was a straightforward proposition. You assembled an army and ordered it to invade. Combat determined the victor. The toll in death and suffering was usually horrific, but it was all done in the open. That is how Alexander overran Persia and how countless conquerors since have bent weaker nations to their will. Invasion is the old-fashioned way.
When the United States joined the race for empire at the end of the 19th century, that was the tactic it used. It sent a large expeditionary force to the Philippines to crush an independence movement, ultimately killing some 200,000 Filipinos. At the other end of the carnage spectrum, it seized Guam without the loss of a single life and Puerto Rico with few casualties. Every time, though, U.S. victory was the result of superior military power. In the few cases when the United States failed, as in its attempt to defend a client regime by suppressing Augusto Cesar Sandino’s nationalist rebellion in Nicaragua during the 1920s and 30s, the failure was also the product of military confrontation. For the United States, as for all warlike nations, military power has traditionally been the decisive factor determining whether it wins or loses its campaigns to capture or subdue other countries. World War II was the climax of that bloody history.
After that war, however, something important changed. The United States no longer felt free to land troops on every foreign shore that was ruled by a government it disliked or considered threatening. Suddenly there was a new constraint: the Red Army. If American troops invaded a country and overthrew its government, the Soviets might respond in kind. Combat between American and Soviet forces could easily escalate into nuclear holocaust, so it had to be avoided at all costs. Yet during the Cold War, the United States remained determined to shape the world according to its liking — perhaps more determined than ever. The United States needed a new weapon. The search led to covert action.