"Correction of a sentence imposed in an illegal manner does not violate double jeopardy even if the correction increases the punishment, and the fact that [the defendant] has commenced serving the sentence is irrelevant."

—since "[i] t would be wasteful to send a case back to a lower court to reinstate a decision which it had already made but which the appellate court concluded should properly be based on another ground within the power of the appellate court to formulate."

Finally, even after the service of a sentence has commenced, the court may make the sentence more severe if it is necessary to bring the sentence up to the minimum required by statute.

A sentence imposed in actual violation of a plea agreement falls within the category of sentences imposed in an illegal manner.

Even after the defendant has commenced to serve his sentence, that power and that obligation continue.

It is well settled that the double jeopardy protection prohibiting the increase of sentence once execution has begun applies only to cases in which the first sentence is valid

Because federal judge's failure to ask offender whether he had anything to say "is an error which is neither jurisdictional nor constitutional [,] collateral relief is not available when all that is shown is a failure to

A sentence inconsistent with a plea agreement cannot be characterized as "illegal", as that term has been applied under Rule 35.

Of course, inadvertent judicial mistakes in imposing sentence may be subject to correction under Rule 35 (a) of the Federal Rules of Criminal Procedure.

[BOOK] Law of sentencing