Many PI cases have been prosecuted on the theory that an intoxicated person merely threatening to operate a vehicle is thereby shown to be intoxicated to the degree, that he may endanger himself or another, spoken of in 49.02, PC. Does the reasoning in Brister have any effect on this rationale? If so, then further proof about the degree of the intoxication may be needed, and alcohol concentration testing is generally not used in these cases.

I don't think that the reasoning from Brister applies. The language of 42.02, by virtue of having the word "may" in it pretty explicitly considers hypothetical danger.

This is in stark contrast to the caselaw and statutes re: deadly weapons. There we MUST engage in a very fact specific analysis of the actual *use* of a particular object. Lots of things can be deadly weapons and can also be completely innocent. (Thomas v. State, 821 S.W.2d 616, 620 (Tex. Crim. App. 1991)(i.e. “automobiles, telephone cords, bathwater, feather pillows, golf clubs or shanks”) That's why the caselaw requires more than theoretical harm. I don't see that there's any such limitation with regard to the "may endanger" language.

I don't disagree that the word may encompasses potential danger rather than actual danger. However, I have always envisioned the word may as an intention to allow officers to intervene before an potential danger becomes an actual danger. For instance, when the intoxicated person is fumbling with his keys and walking to his vehicle, when the intoxicated person is yelling or cursing or shoving but not yet fighting, or when an intoxicated person is standing on the curb or walking towards a street with vehicles and appears to be preparing to cross.

I think those situations are different from an intoxicated person seated on a curb with keys in his pocket but making no attempt to do any of the above.

I'm also not convinced the legislature intended for a blanket rule that every intoxicated passenger being driven by an intoxicated driver is automatically guilty of PI simply by virtue of the fact that the arrest put them in a more difficult position to get home. Certainly there are scenarios where PI makes perfect sense but I begin to worry if we take hypothetical danger too far.

In my experience when prosecutors push the boundaries too far, bad case law results.

One other distinction in the PI law as opposed to deadly weapon is that PI expressly considers someone who may be a danger to himself. Brister specifically said that the driver merely harming himself in a potential accident wouldn't be enough in the DW context.

I may not understand this correctly- are we discussing a passenger in a car (where the driver was arrested for DWI) being charged with PI? If this is the case, then I'd say the "may endanger" is thrown out the window and replaced with "is a danger" to him/her self. (would you get in the car with an intoxicated driver? I think that might be a little dangerous).