Is it legal to kill a home intruder or burglar in the USA?

Depends on the state laws on the matter. If someone were to break into my home, they would die. If they didn't have a weapon, they would by the time the cops got there and that's legal in my state.
It should be.
if you feel your life is in danger, yes......go for it.
If the intruder has a weapon yes, it would be classified as self-defense.
Killing someone does something to yourself in the way of thinking about all the time. Whether it be self defense or selfishness on the others part.
The best thing is to wound in a way to incapacitate them and call the cops.
Family safety is paramount and if you feel threatened IN your home by an intruder that you did not let in, it is legal to defend family and self by use of deadly force.
Deadly force is also legal in Florida on the street if threatened by a bigger aggressor or they also have a weapon.

It's about time
If you are threatened in your home you have the right to defend yourself.
Yes. You can kill any intruder who comes into your home. In any other situation, you must take reasonable care, so the same rules do not govern something that happens in public or even on a piece of property where you do not live. However, you cannot be sued under tort law for liability for killing someone who has intruded in your house. You don't even have to wait to see who it is... if you hear someone coming down the hallway to your bedroom, you can pick up the shotgun and shoot them... it's probably not reasonable since a family member or someone like that could have come over to see you, but if you feel threatened in your home, you can take any action. This rule only applies to your home that you are currently occupying... You can't set up a weapon in your garage that's not attached to your house... then you would be sued.
no, sorry-i think
no if you do kill them that is considered self defense
It depends on the State in which you live; some of the more 'liberal' states, No. The intruder is able to sue you for injuries sustained in the commision of the intrusion, while in other, more 'conservative' states (such as my homestate, Texas), SHOOT FIRST...AND SECOND...maybe ask questions later...
yes- it is self-defense.
The laws very by state, but the most general answer is that you would only be able to claim self-defense if you could show that the burgular presented a clear danger to the life of yourself or family. just by him breaking in does not do this. as far as the part about him having a weapon, this is where the difference in state laws come in, some staes say that if he has a knife you can take him out, others expect you to run away and self defense is not excusable.

no, not in Miami...we have this law on the books for 10 years now!!
its is a grey area. but you are entitled to defend yourself from all crimes not just burglary by using 'reasonable force' . then it is up to the courts to decide if the actions you take are reasonable. if and intruder turns out to be a 5 year old girl merely retreiving a ball or looking for her lost dog then obviously you'll be in big big trouble, on the other hand, if someone breaks in your house armed with a gun and you shoot him dead because you were genuinely in fear you'll be ok, just dont shoot him in the back or they'll say he was not a threat to you since he was retreating. do a search for 'tony martin gypsy murder' he shot a gypsy in the back and got sent to jail, but only cos he shot him in the back