A Texas town is suing the state over its anti-sanctuary city law. You can read about it here:
If you have read the US Constitution, you know it contains the following requirement:
3: The Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution ...
The US Constitution also specifies that Congress establishes the laws regarding naturalization, and that the President has an obligation to faithfully execute our laws.
Putting this all together, should the President fail to execute our laws I believe it falls within the purview of all the other executive and judicial officers to do so in his place. This includes the Governor of Texas.
And if cities in his state fight him, I see no reason why he should not fight back.
Don't mess with Texas.