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.

The policy was the result of African Americans pushing for decades to be recognized as full citizens and part of a trio of amendments — the 13th, 14th and 15th — that ended U.S. slavery and established citizenship and voting rights for some people of color.

Only hours after being sworn into office, President Donald Trump issued an executive order that would end birthright citizenship. Can he do that?