Blakely Waiver

I'm told that what follows is the waiver which is being tried by prosecutors in the federal courts in Virginia:

I am also waiving any right I may have for a jury determination of any and all facts relevant to the application of any Sentencing Guideline factors by the United States District Judge. I agree the District Judge should make the Sentencing Guideline determination using the preponderance of the evidence standard. I understand that by signing this plea agreement I waive any right to a jury determination of sentencing factors that may exist under Blakely and Apprendi, and any case interpreting these two Supreme Court decisions.