You can't fight city hall, they say. Some Texans may be surprised that this saying has its roots in British common law from well before the USA existed. The idea is "sovereign immunity" and is simply that governments are immune from lawsuits brought against them using their own laws.
Texas, like the federal and other state governments, also enjoys this immunity. But like those other governments, Texas has chosen to declare itself partly suable by waiving its immunity under certain circumstances.
There are many disagreements and misunderstandings about this, and the courts continue to rule on issues it raises. To clarify, consider some reasons Texas claims, and waives, its immunity from lawsuits.
Texas is generally immune
At first, it may sound wrong that governments declare their own immunity. But it's seen as necessary to allow governments to govern and police to police without being stopped from reasonably trying to do the people's work.
In a democracy the people are supposed to be the sovereign or ruler. Texas is Texans. Limiting government sovereignty without limiting the people's right of self-governance can get very tricky.
Texas legislators have "absolute immunity" from suits or arrest for what they do while acting in a lawmaking capacity or, for example, speaking during debate. Law enforcement officers such as police, sheriff's deputies and correctional officers have broad immunity for their actions on the job.
Texas waives its immunity in some cases
In a few contexts, the federal government waives its right not to be sued. For example, under the Federal Tort Claims Act, people can sue the U.S. for the misdeeds of people acting on behalf of the United States.
Likewise, the Texas Tort Claims Act partially waives state or local government's immunity if an employee causes injury, death or, in some cases, property damage while acting on behalf of the people of Texas. The same rules of liability applied to private citizens are applied to the government worker, and the law caps the maximum damages that can be awarded.
You could see the Texas Tort Claims Act as a way to limit the damages that can be recovered for government misdeed, and thus limiting government accountability. But in the long historical view over the past 75 years, it's instead (or also) part of a growing trend of state and federal governments choosing to waive some of their long-standing immunity from litigation.