delivered the opinion of the Court.
The issue presented rests upon the initial assumption, which we accept for analytic purposes, that the trial court
*200
erred in a Sentencing Guidelines determination after petitioner’s conviction of a federal offense. The legal error, petitioner alleges, increased his prison sentence by at least 6 months and perhaps by 21 months. We must decide whether this would be “prejudice” under
Strickland
v.
Washington,
I
In the 1980’s and early 1990’s, petitioner Paul Glover was the Vice President and General Counsel of the Chicago Truck Drivers, Helpers, and Warehouse Workers Union (Independent). The evidence showed Glover used his control over the union’s investments to enrich himself and his co-conspirators through kickbacks. When the malfeasance was discovered, he was tried in the United States District Court for the Northern District of Illinois. His first trial ended when the jury could not agree, but a second jury convicted him. The presentence investigation report prepared by the probation office recommended that the convictions for labor racketeering, money laundering, and tax evasion be grouped together under United States Sentencing Commission, Guidelines Manual §3D1.2 (Nov. 1994), which allows the grouping of “counts involving substantially the same harm.” The Government, insisting that the money laundering counts could not be grouped with the other counts, objected to that recommendation, and the District Court held a hearing on the matter. The money laundering counts, it ruled, should not be grouped with Glover’s other offenses. The ruling, as the trial court viewed it, was in conformance with decisions in those Courts of Appeals which had refused to group money laundering counts with other counts for various reasons.
*201
See,
e. g., United States
v.
Lombardi,
On appeal to the Seventh Circuit, Glover’s counsel (the same attorneys who represented him in District Court) did not raise the grouping issue; instead, they concentrated on claims that certain testimony from his first trial should not have been admitted at his second trial and that he should not have been assessed a two-level increase for perjury at his first trial. A short time after argument on Glover’s appeal, a different panel of the Seventh Circuit held that, under some circumstances, grouping of money laundering offenses with other counts was proper under § 3D1.2.
United States
v.
Wilson,
Glover filed a pro se motion to correct his sentence under 28 U. S. C. §2255 (1994 ed., Supp. III). The failure of his counsel to press the grouping issue, he argued, was ineffective assistance, a position confirmed, in his view, by the Court of Appeals’ decision in Wilson. The performance of counsel, he contended, fell below a reasonable standard both at sentencing, when his attorneys did not with any clarity or force contest the Government’s argument, and on appeal, when they did not present the issue in their briefs or call the Wilson decision to the panel’s attention following the oral *202 argument. He further argued that absent the ineffective assistance, his offense level would have been two levels lower, yielding a Guidelines sentencing range of 63 to 78 months. Under this theory, the 84-month sentence he received was an unlawful increase of anywhere between 6 and 21 months.
The District Court denied Glover’s motion, determining that under Seventh Circuit precedent an increase of 6 to 21 months in a defendant’s sentence was not significant enough to amount to prejudice for purposes of
Strickland
v.
Washington, supra.
As a result, the District Court did not decide the issue whether the performance of Glover’s counsel fell below a reasonable standard of competence. On appeal to the Seventh Circuit, the Government argued only that Glover had not suffered prejudice within the meaning of
Strickland.
See App. to Reply Brief for Petitioner 1a-22a. Citing
Durrive
v.
United States,
II
The Government no longer puts forth the proposition that a 6- to 21-month prison term increase is not prejudice under Strickland. It now acknowledges that such a rule, without more, would be “inconsistent with this Court’s cases and unworkable.” Brief for United States 18.
It appears the Seventh Circuit drew the substance of its no-prejudice rule from our opinion in
Lockhart
v.
Fretwell,
The Seventh Circuit’s rule is not well considered in any event, because there is no obvious dividing line by which to measure how much longer a sentence must be for the increase to constitute substantial prejudice. Indeed, it is not even clear if the relevant increase is to be measured in absolute terms or by some fraction of the total authorized sentence. See
Martin
v.
United States,
*205 III
The Government makes various arguments for alternative grounds to affirm the Court of Appeals. Among other contentions, the Government suggests that the failure of Glover’s counsel to argue for grouping of the money laundering counts was not deficient; that Glover’s grouping claim has no legal merit in any event; and that even if Glover had prevailed on his grouping claim, his sentence in fact would have increased as a result. Glover disputes these contentions. We need not describe the arguments in great detail, because despite the fact the parties have joined issue at least in part on these points, they were neither raised in nor passed upon by the Court of Appeals. In the ordinary course we do not decide questions neither raised nor resolved below. See
Taylor
v.
Freeland & Kronz,
The judgment of the Seventh Circuit is reversed. The case is remanded for further proceedings consistent with this opinion.
It is so ordered.
