So I’ve had a bit of experience with the law in a state I don’t keep up with anymore, but let me see if I can paint you the picture of the way the laws intersect.

In texas, there is a specific chapter of the penal code that deals with use of force. The first thing to take note of is that line about “justification” under the chapter being a defense to prosecution. You’ll need to go read a portion of chapter 2 to understand that in full, but suffice it to say a prosecutor could still charge you, and a peace officer could still arrest you, even if the terms for ‘defense’ are met.

Returning to the penal code, 9.51 talks about law enforcement (which is defined in the code of criminal procedure, which we’ll get to in a moment, and which federal law enforcement is also defined) and their authority. If you read it carefully, it basically says they can use whatever force they want to. The qualifier, in 9.51(a), about the actor needing reasonable belief that the force is warranted, lets law enforcement get away with just about everything. There is further clarification on deadly force at 9.51©, which again talks about ‘reasonable belief,’ and on “less-lethal” weaponry at 9.55. The two qualifiers on 9.55 are reasonable belief (it’ll come up again and again in laws relating to use of force) and using it per ‘training.’

Now, if you recall from your internet awareness (which I hope you have), you’ll probably have heard about controversies concerning law enforcement training. ‘Killology’ is the famous one, but every department will have some form of training for all of their tools on the belt, and most of it boils down to “use if if you think you need it” which translates to ‘if they resist and you don’t want to wrestle.’ Every department will have a policy regarding their use, and usually there will be some form of restriction (like don’t use the taser as a cattle prod, which is often ignored) and judicious use of the term ‘reasonable belief.’ Yes, that means that basically departments just throw everything on an officer’s judgement in the moment, because the two requirements in the law simply become one.

Let’s switch gears for just a moment to put some context on officer behavior. Arrests are laid out in the code of criminal procedure, chapters 14 and 15. Fourteen is pretty basic, saying that an officer can arrest for things he witnesses (14.01), and is authorized all measures that could be taken if the arrest was for a warrant (14.05). The rest adds to it, but isn’t important in this case. Fifteen gives us more information (15.24), where it says all reasonable means and force are permitted. It also says you can’t use greater force than necessary, but don’t worry about that, cops don’t worry about it either. I’ll have some comments after the main points.

There are two more bits to hash out. We’ve talked (very briefly) about use of force in arrests, and those statutes touched on searches (which is mildly more difficult, mostly because we’d have to go into case law where searches really get hammered out), but we haven’t talked about ‘defense’ of person or property. Law enforcement has their own rules for arrests and certain actions like traffic stops, but they have the same laws for defending against assault/damage (except where courts have let things proceed differently, which you’ll have to understand is a weird thing where laws are shaped in court as much as in the legislature), so that brings us to 9.31 and 9.41 of the penal code. I’m sort of getting weary of quoting, so I’m going to paraphrase these sections quickly. You can stop someone from hurting someone else, and kill them to prevent them killing someone else, if you have a reasonable belief about it. You can stop someone from taking stuff, or damaging stuff, if you have a reasonable belief about it. You can also kill to prevent certain crimes against property, if you have a reasonable belief.

So now we can answer your main question: how are they allowed to, or how are they skirting the laws? It’s because they’re not skirting the laws. Almost every department policy can be summarized as throwing things back to having a ‘reasonable belief.’ Reasonable belief is the great wall of china that every complaint and investigation about law enforcement must crest… and it’s a difficult barrier to overcome. This is because reasonable belief is going to be, one, in the mind of any law enforcement member who is thinking about whether another member’s actions were criminal. If the investigating member can put themselves in the shoes of the other and even for a split second imagine doing the same thing, that investigation is going to die. Reasonable belief, two, is then going to be argued about in the prosecutor’s office, where they generally want a decent working relationship with police agencies, and, three, in court, where we’ve seen plenty of actions die in the grand jury and jury box. Ice isn’t ‘getting away’ with their outrages so much as simply doing what every other law enforcement agency does. The only difference is that they are blatantly violating the one area where the courts (typically, before now) have been willing to ensure law enforcement follows the law: having probable cause to arrest (so, more than ‘just’ being darker skinned), and thus not violating civil rights. Seeing as we’ve just had the supreme court throw out that shit, we’re fucked in that regard.

To return to a few things that I mentioned and wanted to talk about more (mostly because they’re not directly relevant to your question of ‘how?’ but are things to know in the general sense, and a big warning besides): justification/defense, and using force against peace officers. If you remember, I was paraphrasing the second chapter of the penal code where it says a prosecutor doesn’t have to deny the defense in their charging statement. However, in practice it is almost always done. There’s a giant book out there for prosecutors that has example charging statements for just about every crime ever, and the majority of them are simple recitations of a crime’s major points, and typically refute any possible defense claims. This means prosecutors, and the officers who use the very helpful example statements, will very, very rarely make an arrest and press charges if the defense can’t be refuted in the charging statement. Note that recent case in texas where someone shot a kid for ding-dong-ditching, and he wasn’t arrested immediately (I might be misremembering this case and another one where any normal person would be screaming "Why didn’t they arrest him?! Texas seems to have a lot of those). This is a ‘privilege’ that is extended much more often to other law enforcement fucks.

Now we come to where most of us need to be very careful. 9.31© of the penal code talks about resisting peace officers. America has had some famous examples of that, such as the military member who shot back when a no-knock warrant was executed on the wrong house. The issue is that each officer gets judged by their reasonable belief. Remember, everything comes back to reasonable belief. If an officer tells you that you are under arrest, and you are completely compliant, if the officer suddenly pulled out their taser and begins using it on you, I (and hopefully a jury) would say you are completely justified in resisting. But what happens if you knock the taser out of the officer’s hand? Do you then get to run away from said officer? What if another officer pulls up and sees you swinging your fists/feet/body at the other officer who has already deployed a taser? Most departments preach about having a lethal weapon covering a situation if a taser is being deployed. That means this second officer is going to be primed to shoot (and their lawyers can write up that 'reasonable belief) faster than I could find the statutes website for this post). Now what if the second officer was two or three officers down in the little police red-rover line they like to pull, and didn’t see whether you did something to make a taser reasonable? What if it wasn’t a taser, but a gun, and you responded with your own? It’s all bullshit, but it’s shit that will get you killed and the police a pat on the back from their asshole colleagues.