It is a spaniel type dog that is closely related to the English Cocker Spaniel; the two breeds diverged during the 20th century due to differing breed standards in the US and the UK. It was not until 1970 that The Kennel Club in the UK recognized the American Cocker Spaniel as being separate from the English type. The American Cocker was the most popular breed in the United States during the 1940s and 1950s and again during the 1980s, reigning for a total of 18 years. They have also won the best in show title at the Westminster Kennel Club Dog Show on four occasions, the best in show title at Crufts in 2017, and have been linked to the President of the United States on several occasions, with owners including Richard Nixon and Harry S. Truman. American Cockers previously high popularity resulted in the breed frequently being bred by backyard breeders or in puppy mills. This indiscriminate breeding has increased the proliferation of breed related health issues in certain bloodlines.