You are correct. This will be the direct result of this decision. All gang murders will now be done by those under 18, with the most they can be punished is a few years in jail.
I disagree. Do you really beleive the death penalty is a deterrent? I don't. If it was, the states which have the death penalty would have fewer murders, and the opposite would be true in states that do not.
I don't think it will be that direct, but it will continue to foster an attitude of "FU, You can't do sh!t to me, mutha-funka. I bust off a cap in yo @ss." It will also probably make the prison guards jobs harder... they already have to kiss their @sses. Its a wonder we have any guards left, not to mention police.