Political Wire put up a link this morning to the US Equal Employment Opportunity Commission website, which includes this information:

Harassment Based on National Origin Ethnic slurs and other verbal or physical conduct because of nationality are illegal if they are severe or pervasive and create an intimidating, hostile or offensive working environment, interfere with work performance, or negatively affect job opportunities. Examples of potentially unlawful conduct include insults, taunting, or ethnic epithets, such as making fun of a person's foreign accent or comments like, "Go back to where you came from, " whether made by supervisors or by co-workers. [emphases added]

I’d describe Trump as a “co-worker” given that Congress is a co-equal branch of government. Definitely applies to Ilhan Omar and probably to the others, given that the law recognizes a perception of nationality as sufficient to charge discrimination.

Shall we make this Article of Impeachment number 1,837?

[Update] Although the point below was made somewhat intemperately, it is technically correct that this is employment law, and Trump really didn’t break it (though I could still say he is trying to create an hostile work environment). The point of the EEOC paragraph is that it gives “go back...” as a specific example of an illegal comment which constitutes harassment on the basis of national origin. After thinking about this some more, I decided to soften the title.