Eighteen states and the ACLU filed lawsuits seeking to prevent President Trump from denying citizenship to children born in the U.S. to non-citizens.

The American Civil Liberties Union on Monday night filed a lawsuit challenging President Donald Trump's controversial executive order that seeks to end birthright citizenship.

Put simply, under Trump’s order, the children of most undocumented immigrants wouldn’t be US citizens, nor would the children of people in the country on student, work, or tourist visas. This is more than a reinterpretation of the 14th Amendment — it’s an attempt to do away with the jus soli principle that undergirds US citizenship.