Just got a "breaking news" flash. Eighteen states have sued over the birthright citizenship EO. Less than one day in office.

Yep. That's the second lawsuit on that EO. The first was filed in New Hampshire by a bunch of non-profit advocacy groups; this one was filed in Massachusetts. Links below.

Two things about the suits that are in line with what we've been discussing:

1) Both of them were filed in states that are part of the First Circuit Court of Appeals. In this type of federal litigation, the plaintiffs get to choose where they file their suits. The one thing that's special about the First Circuit is that there are no Trump appointees on the court. There is a vacancy, so that might change, but even then they would be the only such judge.

2) Both suits include APA claims. If any agency changes how it treats the citizenship status of people in the U.S., that's a new substantive rule being applied by the agency - so it has to go through the APA. So both groups have sought injunctions against all of the relevant agencies to make sure they don't implement this EO, because none of the agencies have taken the steps required by the APA.

storage.courtlistener.com: PDF document
fingfx.thomsonreuters.com: PDF document