In the middle of this extremely good rundown/argument why this is so, we find inevitable reference to Obama on DACA vs. Trump on the wall, as some are arguing in a sauce for goose, sauce for gander application.
Difference: Obama in DACA order went directly contrary to Congressional decision, Trump in case of wall wants to implement what Congress authorized, using money as Congress has allowed.
Read this enlightening piece.
Blithe Spirit 