Barack Obama: “Ukraine's continuing courageous leadership on nuclear security is commendable.”

It is a basic principle of American democracy that the government can’t selectively target individuals simply because of their political beliefs or what they say.

The effort, he said, “should outrage all Americans, regardless of how they feel about Congresswoman Omar’s political views.”

People need to “rediscover what’s the story we tell about how we’re going to live together, and see each other, and recognise each other, and disagree, and yet, still care for each other”.

The fact that any president, or any administration, is willing to engage in such transparent efforts to intimidate someone should outrage all Americans, regardless of how they feel about Congresswoman Omar’s political views.