President Donald Trump’s executive order denying U.S. citizenship to the children of parents living in the country illegally has faced the first of what will be many legal tests.

Around three dozen countries and the U.S. offer automatic citizenship to children born within their borders, regardless of their parents immigration status.

The14th Amendment was intended to correct the moral wrongs of slavery. But it has been misunderstood and reinterpreted in cases involving workdays, schools, train cars and birth control.