There was never a “the Know Nothing Party”.
It was actually the American Party, known as the Native American Party before 1855.
The Know Nothing Party was a 19th-century US political party primarily known for
its strong anti-immigrant and anti-Catholic sentiments, often referred to as “nativist” views.
They were named “Know-Nothing” because they would claim to “know nothing”
about their party’s secretive activities when asked about them.