You can't execute someone
more.
In most American States there is a death penalty for what we call Murder in the First Degree, which is premeditated murder. Hate crime killings would have to be included in this definition, and therefore those who perform them would be subject to the same sentence - execution.
The distinction between hate crime and non-hate crime would either require a way to execute someone more, or a lessened sentence for non-hate crime 1st degree murders which would likely consist of life sentences, which in America mean about 10 years in prison with parole. The people who are pushing for hate crime legislation are concerned with placing hate crime in the current top spots for sentencing, and reducing sentencing for non-hate crime because they feel that there is a distinction between the exact same crimes when there is the possibility of involvement with a prejudice of some sort. This is as ridiculous as sentencing someone more harshly for killing someone with a handgun than killing them with a chainsaw - because of a personal vendetta against handguns. The crime is still murder, and to be honest, I think it would be much less painful to be shot in the head and instantly killed than chainsawed to death. However, this is yet another instance where people's feelings on a hotbed issue causes them to overreact and project into a sphere where there is no merit.
If someone commits violent crime, it doesn't matter why they committed it. Someone else is a victim, and that victim (which represents society) deserves the same justice as any other victim of the same crime, regardless of the motive.
Assuming that motives can be a factor in sentencing is a slippery slope, and not one that will end in a cushion of pillows. First of all, you have to prove motives, which means you have to prove what someone was thinking. From there, this train of logic assumes it is ethically and morally acceptable to punish someone for what they thought, rather than what they did. This is just not acceptable in the free world, no matter how depraved someone's thoughts were. We are judged by our actions, not our thoughts, lest we all be judged - and most likely unjustly.
Hate crime legislation is thought policing, pure and simple. I'm against it, and I always will be.
Edit: As a side note, and as politically incorrect as it may be... in this same nation that is pushing for hate crime legislation, white people are 13 times more likely to be the victim of violent crime by non-white people than non-white people are likely to be the victim of violent crime by white people. If hate crime legislation were passed, a huge population of violent crime would be applicable simply because it crossed racial lines, and would end up being more harmful to many of the minority groups it was trying to protect than not.
Hate crime legislation is short sighted and only capable of creating precedent for the government to assert more control over the masses. Passing it will only result in a massive backfire.