appealed his original conviction; "[i]n order to assure the absence of such a motivation [vindictiveness], we have concluded that whenever a judge imposes a more severe sentence upon a defendant after a new trial, the reasons for his doing so must affirmatively appear . . . [a]nd the factual data upon which the increased sentence is based must be made part of the record, so that the constitutional legitimacy of the increased sentence may be fully reviewed on appeal.” North Carolina v. Pearce, 395 U. S. 711, 726, supra. Subsequent decisions have illustrated that it is the possibility of vindictiveness in an appellate procedure and in resentencing that violates due process and not merely the possibility that a harsher sentence may be imposed. Colten v. Kentucky, 407 U. S. 104, supra (<HOLDING>); Chaffin v. Stynchcombe, 412 U. S. 17, supra
holding that a court of appeals should review de novo a district courts determination of state law holding that the possibility of vindictiveness does not inhere in a twotier system of appeals with the right to a de novo hearing after conviction in an inferior court holding in the criminal context that a district courts obligation to make a de novo determination with respect to the portions of a magistrate judges report and recommendation to which objections are made did not require a de novo hearing holding that presumption of vindictiveness is inapplicable in a system which gave a convicted defendant the right to a trial de novo in another court holding that there is a presumption of vindictiveness when a harsher sentence is imposed after a defendant exercises his right to a de novo review