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.

Trump's executive order on birthright citizenship would affect 2 members of NH Indonesian Community Support, who are expecting a child in February.

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.

ALCU Deputy Director Lee Gelernt and Immigration Attorney Michelle Canero speak to NBC News' Tom Llamas about President Trump's executive order on challenging birthright citizenship and what this could mean for Americans.

This story was updated on Jan. 21 at 6:08 p.m. to reflect that the ACLU’s lawsuit was filed on Monday, not Tuesday. Hours after President Donald Trump issued an executive order Monday barring birthright citizenship to children of undocumented residents,

The American Civil Liberties Union (ACLU), along with several other pro-immigrant groups, is suing the Trump administration after President Donald Trump signed an executive order that seeks to end the constitutionally recognized right of birthright citizenship. The 14th Amendment of the U.S. Constitution states in its first sentence that:

New Hampshire Indonesian Community Support and two other organizations are challenging an executive order signed late Monday that would end birthright citizenship for the children of some immigrants.