It's more humane and reliable than the electric chair. Lethal injection is definitely not a perfect method but how much do we owe people who have murdered, raped, and tortured other people? It's more than they deserve.
Not really.. Firstly, there have been numerous cases of the wrong people being charged and convicted. Secondly, we are not animals or savages! Hence, we have courts and law to punish the relevant people, the solution is not becoming worse than they are!
Death is the punishment the prisoner is getting for his/her offenses. We have an obligation to make sure state-sanctioned murder is different from the murder that put the prisoner there in the first place. Lethal injection has been proven to be inefficient and painful.
It is the most humane method we have developed so far. What do you suggest instead?