How is issuing executive orders negating enforcement of part of the law substantively different from the line-item veto power the Supreme Court has already ruled unconstitutional?
Because the money would still get spent.
Would the money still be spent on enforcing the law created by Congress? Given that the executive order explicitly states that it would not enforce the law for a certain class of people, how can that be interpret as anything other than a "creative reinterpretation" of the law as Congress passed it?
If the appropriation was hyperspecific as to what the funds could only be spent on, but I sincerely doubt that it gets to the point of specifying for example that $78 million dollars shall be spent on enforcement activities against those who have overstayed tourist visas from Ireland. It's not as if there won't still be plenty of deportations, it's just that the focus would be even more against those newly arrived and on those who did any non-immigration crimes here than is now the case.
