American historians knew about it but did not know how to handle it. Or claimed they did not.
Abraham Lincoln got the (North) interested in the occult because he dabbled in it. Supposed to have had a seance in the White House.
Sir Arthur Conan Doyle was a Dr. and a brilliant writer yet he believed in some of the hocus pocus. He and Lady Doyle tried to contact their Son who was killed in WWI. His friend Houdini knew they were fakes and showed Doyle how they were done.
Still Doyle continued to believe.
Hillary Clinton actually did a psychological exercise where she “communed” with the spirit of Eleanor Roosevelt.
Snopes.com investigated it and deemed it to be mostly true.