The relationship between China and the U.S. is now one of the most important bilateral relationships in the world, and every successive U.S. president, except Jimmy Carter, has visited China. The trip is consistently ranked by historians, scholars, and journalists as one of the most important—if not the most important—visits by a U.S. president anywhere. Also, a "Nixon to China" moment has since become a metaphor to refer to the ability of a politician with an unassailable reputation among their supporters for representing and defending their values to take actions that would draw their criticism and even opposition if taken by someone without those credentials.