The bill would allow the State of Texas to void any federal law that conflicts with the Texas Bill of Rights. I suspect that what Sen. Hall is getting at is Sec. 23 of the Texas Bill of Rights, the "Right to Bear Arms." This would be in keeping with his assertions that the federal government under Pres. Obama is out to take away everyone's guns (no telling how he feels about whether President-Elect Trump will attempt the same). I've reached out to his office for clarity on his motivations for this bill,
Regardless of his motivation, the affect of the bill (were it to pass (unlikely) and not be immediately struck down by the courts (even less likely)) would be to nullify the affect of the Supreme Court's ruling in Obergerfell, which made the freedom to marry the law of the land.
One of the truly nasty things about the passage of Texas' anti-marriage constitutional amendment in 2005 is that the amendment was put into the state bill of rights. That's right, right there in Article I, sec 32 of the constitution, between the rights of crime victims and the right to hunt is the rather torturous inclusion of a negative right: the right to not have the right to marry. SB 89 would elevate that amendment above the law of the land, allowing Texas to ignore the freedom to marry.
In legal terms this is called 'state nullification' and it's utter hokum thoroughly discredited in case law. For example, in Cooper v. Aaron the Supreme Court rejected an attempt by the State of Arkansas to nullify the court's decision in Brown v. the Board of Education (recognizing segregation as unconstitutional). State's simply can not ignore federal law whenever they want - which is exactly what Sen. Hall's bill is attempting to do.
In Cooper the court said
"Article VI of the Constitution makes the Constitution the "supreme Law of the Land." In 1803, Chief Justice Marshall, speaking for a unanimous Court, referring to the Constitution as "the fundamental and paramount law of the nation," declared in the notable case of Marbury v. Madison, 1 Cranch 137, 5 U. S. 177, that "It is emphatically the province and duty of the judicial department to say what the law is." This decision declared the basic principle that the federal judiciary is supreme in the exposition of the law of the Constitution, and that principle has ever since been respected by this Court and the Country as a permanent and indispensable feature of our constitutional system. It follows that the interpretation of the Fourteenth Amendment enunciated by this Court in the Brown case is the supreme law of the land, and Art. VI of the Constitution makes it of binding effect on the States "any Thing in the Constitution or Laws of any State to the Contrary notwithstanding." Every state legislator and executive and judicial officer is solemnly committed by oath taken pursuant to Art. VI, cl. 3 "to support this Constitution." Chief Justice Taney, speaking for a unanimous Court in 1859, said that this requirement reflected the framers'"Obergerfell, similarly, is a fourteenth amendment case. Sen. Hall is pulling at the threads of civil rights law in America. His bill threatens to unravel the advances of the last half century.