Most of you know that the police have been militarizing for around the past twenty years. I don't like that. I don't mind them having armored vehicles so much as I'm unnerved by the increased use of automatic weapons and tear gas.
What's particularly wrong with tear gas? The military isn't allowed to use it (although it's not a war crime, there is a possibility of other, much less pleasant gases being used as a response). Although I don't object to police having access to tear gas to deal with violent crowds, it hasn't just been used for that purpose. Not only should it not be used against nonviolent targets, but even against violent targets, extreme care should be taken in its use. Tear gas grenades are a fire hazard, as anybody who knows how the Waco siege ended can tell you (if you're not familiar with what happened, there was this cult in Texas, federal law enforcement decided to show up, they borrowed a few tanks from the Army which they had no need for, they camped out near the cult's compound for a few weeks, and at the end, they threw tear gas in, causing a fire in which 76 people died, including 20 children and two pregnant women). They function by burning a solid block of the chemical and releasing it into the air. For this reason, it should not be used except against violent crowds AFTER the area has been determined to be relatively safe with regard to fire hazards.
Police should also not have nearly as many automatic weapons (machine guns) as they do. If it's larger than pistol caliber (due to the reduced stopping power) and will not be used from a boat (due to the increased difficulty in hitting the target when in a boat), police have no reason to use them. The main reason why automatic firepower is used in land-based tactics is to provide suppressive fire (forcing people to keep their heads down), which I can't even imagine SWAT having any need for. Most police officers who I've heard say things about this agree that there's no need and say that they (like the military) rarely use the automatic setting, so as to conserve ammunition.
The reason why I think (and hope) police have been acquiring automatic weapons even if they never use the automatic setting is because they want to be able to fire automatic weapons without having to rent one for several hundred dollars per minute or buying one for several thousand dollars at minimum. Because of an amendment to the 1986 Firearm Owners' Protection Act (which mostly says that if you're just passing through a state and spending shorter than 24 hours, you can bring with you firearms which would otherwise be illegal in that state), it has been illegal for anybody but manufacturers, military, and police to possess newly-made automatic weapons. For this reason, the prices of the 250,000 transferable automatic weapons have increased drastically (I could make a very strong argument that it is a form of class warfare to restrict certain types of firearm to the extremely wealthy, but that is not the topic at hand). Police do not have to pay such high prices since they are able to buy automatic weapons made after 1986, For example, a $15-20,000 M16 variant would cost $1,200 at most for a police department. I think and I hope that the reason why police departments have acquired a lot of such firepower recently is because they're the only people who can.