That was their reason for claiming 'standing'.

DAPA was challenged originally on procedural grounds. The lawsuit, State of Texas, et. al, v. U.S., alleged that the Obama administration does not have the executive authority to implement these programs as executive actions without first going through the normal regulatory process.

And in order to prevent implementation of the programs while the lawsuit progresses to a merit hearing and final decision, the States sought and obtained a temporary injunction. Originally, Judge Andrew Hanen of the U.S. District Court for the Southern District of Texas Brownsville Division granted a temporary injunction around February 2015, and the Fifth Circuit Court of Appeals upheld the injunction the following November. Finally the Supreme Court in turn upheld the injunction by a 4-4 tie - whenever the U.S. Supreme Court is evenly split, the lower court ruling stands, which in this case meant that the lower courts injunction is upheld.

Lets not get into whether or whether not the state of Texas even had standing to sue. The Obama administration contended that it did not - as in fact, much of the hearing was spent deliberating on this matter.

But the substantial question at issue is that the current Attorney General himself is on record as casting doubt on the Constitutionality of DACA during his confirmation hearing. Indeed, he has explicitly stated that he believed it to be unconstitutional: [Around 11:30 am]

https://www.c-span.org/video/?c4647256/sessions-daca

Then their is Gorsuch, our 9th Supreme Court Justice who by all measures is more Catholic than the Pope, as the saying goes - i.e. more Scalia than Scalia, as measured on the "Scalia Index" (yes, that's a thing), and everything that entails for immigration.

http://www.nydailynews.com/news/poli...icle-1.3278953

Finally, their is daddy Trump himself - a president with a flagging approval rating, beset by controversy and increasingly viewed (by Republicans) as a liability during the upcoming mid-term elections.

Without presuming to understand the inner workings of this quaint creature, it maybe safe, at a minimum, to assume self-interest and desire to maintain the popularity he enjoys with his base to be a sufficient incentive for him to offer us up if things start to go badly.

But again, this is all too premature. Time and more information will tell; especially as to how the administration responds to the letter, if at all.