1.) Virginia Circuit Court Judges use the Sentencing Guidelines as a tool to assist the Judge in fixing an appropriate punishment and are not bound by them, I am assuming that Blakely decision does not apply in Virginia?1) You are correct: Blakely will not apply to Virginia's guidelines. In making the guidelines discretionary our Legislature did not set a mandatory maximum penalty per the guidelines and as long as the judge does not exceed the actual maximum punishment set out by the statute the length of the sentence is unreviewable.
2.) The "Sentence Reform Act" was inacted to prevent disaparity in sentencing. Why does and how can Virginia Courts only use the Sentence Guidelines voluntarily and not mandatory?
2) Why? I think because in most cases this works well. Judges are able to fashion just sentences when factors other than those considered under the guidelines should be considered. In some cases it fails when the judge goes back in and decides that a factor already considered by the guidelines should lead to a departure. I see more downward departures and they tend to be smaller departures of 12 months or less (usually less). Upward departures though more seldom seen are usually more massive; once a judge decides to depart upward he is usually thinking logarithmically. Still, all-in-all the guidelines work because they are followed 80% of the time.
How? You must remember that judges in Virginia are creatures of the Legislature. Effectively, this means they are probably among the least protected judges in the nation. Federal judges sit for life and many State judges are elected so that once they are seated they really don't face the wrath of the Legislature or the Executive. In Virginia all judges go back in front of the Legislature every so often to get voted back in at the whim of the legislators. Therefore, a judge in Virginia who flaunted the guidelines would have to face a Legislature not happy with the open defiance.
[comment] The obvious flaw in this system is that a law-and-order Legislature will not likely punish massive upward departures but might punish downward departures by removing a judge. In the last legislative term this appears to have happened to a judge who ran afoul MADD et al. by trying not to destroy people's lives with the increasingly draconian DUI laws. Of course, it didn't help that it was the same year that a legislator lining himself up to run for higher office was pushing even more draconian DUI statutes. Judges notice these things.