Why Britain and the United States became close allies

Why could Britain and the United States become close allies so readily?

Atlantic geography and a common language helped, but both sides also made a sustained effort to understand one another.

Geography comes first: the Atlantic connected the strategic concerns of Britain and the United States even while separating them physically. A common language reduced some barriers to cooperation, though neither factor made closeness automatic. Leaders and institutions on both sides repeatedly invested time in understanding how the other country thought and operated.