Donald Trump has denied sparking a storm with his remarks on migrants last week; but there are many other world leaders whose condemnation of migrants has been all too clear.
Across Europe, leaders in Hungary, the Czech Republic and Poland all have described migrants variously as "poisonous, disease-ridden or criminals."
Political and historical sociologist Ulrike Vieten says language that seeks to demonise and denigrate migrants threatens to become widely accepted.
"It creates a climate where any other person, migrants, refugees, asylum seekers don't feel welcome any longer. We have a position where there's a "them and us" constructed and perpetuated," said Vieten.
"In different ways, people or minorities, or those who have less, let's say privilege or legal rights to stay anywhere, are scared and have good reason to be scared."
Two years ago, Pete Hoekstra, the new US ambassador to the Netherlands said Muslim migrants had sown chaos in the country. But last week he refused to expand on his comments after his inauguaration ceremony. Although he's since apologised Dr Vieten says the damage has already been done.
"If we don't challenge these kind of statements, this kind of politics (then) we really become like in the last century in the early 1930's when Jews were basically humiliated and people just got on with their lives."