Rappaport’s Law enforced strict segregation between the No-Maj and wizarding communities. Wizards were no longer allowed to befriend or marry No-Majs. Penalties for fraternising with No-Majs were harsh. Communication with No-Majs was limited to that necessary to perform daily activities.
From Rappaport’s Law, on the Pottermore site.
Interesting. My headcanon that Magical secrecy was more lenient in America was wrong, but here’s another interesting piece of information.
This common endeavour led to no softening on MACUSA’s stance on No-Maj/wizard fraternisation, and Rappaport’s Law remained firmly in place. By the 1920s the US wizarding community had become used to existing under a greater degree of secrecy than their European counterparts and to selecting their mates strictly from within their own ranks.
This law was still in affect by at least the 1920s, if it’s not currently still in place.
Which... could possibly mean some horrifying scenarios for muggleborns (like Tech) and squibs (like Sky) which could be really interesting.