Ronald Reagan received a letter that said:
"You can live in France, but you cannot become a Frenchman. You can go to Germany or Turkey or Japan, but you cannot become a German, a Turk or a Japanese. But anyone, from any corner of the Earth, can come to live in America and become an American. "
Reagan's response:
"Other countries may seek to compete with us; but in one vital area, as a beacon of freedom and opportunity that draws people of the world, no country on earth comes close... If we ever closed the door to new Americans, our leadership in the world would soon be lost."
Just for clarity and background:
Last week Donald Trump tweeted that four congresswomen of color should "go back" to the countries they came from even though they are all American citizens and three were born here. (To say nothing of the fact that they were all legitimately elected to Congress). One is a naturalized citizen, as is Melania Trump.
He further stated that they "came from countries whose governments are a complete and total catastrophe, the worst, most corrupt and inept anywhere in the world.... why don't they go back and help fix the totally broken and crime infested places from which they came."
Funny, that's exactly what they're trying to do.