In 1823, the what act emerged, stating among other things that europeans should not interfere with american nations.

The correct answer is:

The Monroe Doctrine.

The Monroe Doctrine was a United States policy that opposed European colonialism in the Americas. It declared that farther attempts by European countries to take control of an independent state in North or South America would be seen as hostile.

At the same time, the U.S. would acknowledge and not interpose with existing European colonies neither interfere in the internal affairs of European countries.

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.