J.K. Rowling has already established what drove American wizards and witches further underground, and in her final History of Magic in North America story, the Harry Potter scribe details the effects the institutionalized segregation of Rappaport's Law had on the magic community in 1920s America.
Pay attention, Potter fans. This information is crucial for understanding the fractured world British magizoologist Newt Scamander (Eddie Redmayne) steps into in Fantastic Beasts and Where To Find Them.
According to Rowling's account of "1920s Wizarding America," legislation introduced in the 1800s required every member of the magical community in America to carry a "wand permit." By legally registering wands, the Magical Congress of the United States of America (MACUSA) could better monitor "all magical activity and identify the perpetrators by their wands" when laws were broken. They were extreme measures, but measures Congress felt were necessary to keep their wizards safe.
In fact, MACUSA was so determined not to have another near-catastrophic security breach that they even became intolerant of such magical phenomena as ghosts, poltergeists, and fantastic creatures "because of the risk such beasts and spirits posed of alerting No-Majs to the existence of magic."
Fantastic creatures, huh? We don't think Madam Seraphina Picquery (played by Carmen Ejogo in Fantastic Beasts) -- the president of MACUSA throughout the 1920s -- will be too happy when she finds out Newt accidentally let some of his rare and endangered magical creatures escape for all No-Majs to see. Hopefully, she doesn't have to use her Beauvais wand on him. (More on that in a bit.)
Speaking of wands, even though North American wizards practiced wandless magic for centuries, by the time European wizards immigrated to the New World, they brought a few of their comforts from home with them, like wands. By the 1920s, wand proficiency was mandatory for all students at Ilvermorny School of Witchcraft and Wizardry.
Purchasing a wand, however, presented its own set of unique challenges. Unlike Britain, where Ollivanders was highly considered to be the best wandmaker in the game, the continent of North America was served by four great wandmakers. So when choosing a wand, a wizard had to think of what kind of statement he or she wanted to make.
Shikoba Wolfe, of Chocktaw descent, was primarily known for "intricately carved wands containing Thunderbird tail feathers (the Thunderbird is a magical American bird closely related to the phoenix)." A Wolfe wand was prized by Transfigurers, as they were extremely powerful and very difficult to master.
Johannes Jonker, a Muggle-born wizard, created wands that were instantly recognizable among wizards and witches, as "they were usually inlaid with mother-of-pearl." The core of a Jonker wand was a single hair of the Wampus cat.
Meanwhile, Thiago Quintana was a trendsetter of sorts. His wands were famous for being sleek and usually lengthy, "each encasing a single translucent spine from the back of the White River Monsters of Arkansas and producing spells of force and elegance." Only Quintana knew the secret of luring a White River Monster, and he took that secret to his death. Therefore, wands containing White River Monster spines have since ceased production -- so an original remains extremely valuable.
Lastly, Violetta Beauvais, the famous wandmaker of New Orleans, crafted beautiful wands made of swamp mayhaw wood, the core of which contained "hair of the rougarou," a dangerous dog-headed monster that prowled throughout the Louisiana swamps. "It was often said of Beauvais wands that they took to Dark magic like vampires to blood," Rowling wrote, "Yet many an American wizarding hero of the 1920s went into battle armed only with a Beauvais wand, and President Picquery herself was known to possess one."
To some extent, MACUSA will probably play an antagonistic role in Fantastic Beasts. That's not to say President Picquery is a dictator drunk on power -- or, "Gigglewater." In fact, it's quite the opposite. MACUSA has implemented these laws to protect their people from persecution, as the Scourers still possess a dangerous threat to wizards. So when Newt arrives in New York City and quite literally blows up their spot, MACUSA has a right to be mad.
That being said, segregation of the wizarding and No-Maj communities is not the best way to go about things, and something tells me that even President Picquery knows it.
After all, she seems pretty chill under that hardened exterior. While the No-Majes were prohibited from consuming alcohol in the 1920s, MACUSA allowed their wizards to drink (in moderation, of course, as drinking and practicing magic is still an explosive combination). President Picquery was even heard to say that being a wizard in America was already hard enough, reportedly telling her staff "The Gigglewater is non-negotiable."