Anthony Johnson appeals from the sentence the District Court1 imposed upon him after he pleaded guilty to one count of an indictment charging him with being a felon in possession of a firearm.2 We affirm.
Under the Sentencing Guidelines, a two-level adjustment to a defendant’s base offense level is warranted if “the defendant willfully obstructed or impeded, or attempted to obstruct or impede, the administration of justice during the course of the investigation, prosecution, or sentencing of the instant offense of conviction.” U.S. Sentencing Guidelines Manual § 3C1.1 (2001). The adjustment applies to conduct that includes “committing, suborning, or attempting to suborn perjury.” Id. cmt. n. 4(b). The enhancement was recommended in this case based on the contents of a letter Johnson wrote to Lloyd McCawley while McCawley was incarcerated in a Missouri state correctional facility. The District Court found that the letter’s “context and syntax” reflected an attempt to suborn perjury. Transcript of Sentencing Proceedings at 14. The court further noted, “[T]here was an attempt to create testimony. And when one is attempting to create testimony it’s because it’s not true.” Id. The court found that Johnson’s attempt was willful and that the testimony he attempted to induce would have been materi*819al to his sentencing had the relevant sentencing reductions (for diminished capacity and for possessing a firearm only for sporting purposes) been pursued. The court therefore concluded that the facts supported a finding of an attempt to obstruct justice and increased Johnson’s base offense level by two levels.3 Johnson contends that the letter alone is insufficient evidence that he attempted to suborn per-jurious testimony from McCawley. “An enhancement for obstruction of justice is based on findings of fact, which we review for clear error.” United States v. Vaca, 289 F.3d 1046, 1049 (8th Cir.2002).
The letter in question opens with Johnson telling McCawley that “they got me” and that he, Johnson, would plead guilty and seek a reduced sentence for diminished mental capacity. Letter from Anthony Johnson to Lloyd McCawley (Jan.2000).4 He tells McCawley, “I’m going to need you to testify to the following for me at sentencing. Read this over and over good before you come to court. Stories have to match — OK!” Id. What follows then is a chronology of their alleged activities just prior to Johnson’s arrest on the firearms charge. Johnson uses phrases such as “You drove me,” “You and Maurice carried me,” “Say you told Maurice to tell me.” Id. The letter recounts events and conversations that Johnson could not have witnessed, as they would have occurred, if at all, when Johnson was passed out or not present. See, e.g., id. (“About an hour later [after Johnson had left the apartment] you started to worry about me and the telephone rang.... After Maurice hung up the telephone you asked Maurice what I was in jail for.”) Regarding the gun found on the floorboard of the car that Johnson was driving when he was arrested, Johnson directs McCawley:
(Say Maurice asked you why you let me take his car, I said I was going to walk) It is Maurice’s Target Pistol a 32. Caliber R.G. Modle (sic) revover (sic), black with a brown handle with tape on it. Make sure you say it was a TARGET PISTOL AND Maurice had it for target shooting only “not for self defense” because I can get my sentence reduced if also if I obtained or possessed the firearm or ammunition soley for lawful sporting purposes or collection. They got me cause the bullets I had in my coat pocket carry the same time as the gun. I’m sending a copy of the police report so you will understand what and why to say (unknown) above. I am writing Maurice and getting him to say the same thing.
Id. Finally, Johnson asks McCawley to “[t]ell them I have the same mental impairment as Mahummad Ali. Brain Syndrome, and I need Adult Supervision.” Id. That is followed by a detailed list of the purported manifestations of his “impairment,” including, “I don’t think clearly and make logical and rantional choices and decisions .... I forget simple stuff .... Slow on thinking. Can’t keep up with dates, events, appointments and stuff.” Id. Yet Johnson wrote a detailed description of events that would have occurred two years earlier in order to have McCawley assist his attempt to get his sentence reduced— behavior that is neither illogical nor irrational. The letter itself reflects clear *820thinking and great attention to detail and belies Johnson’s alleged “impairment.” And notwithstanding Johnson’s claim that the facts set out in the letter are true, he did not argue at his sentencing for reductions in his sentence on the grounds of diminished capacity or possession of a firearm or ammunition only for sporting purposes.
We do not think the court erred in relying solely on the letter in finding by a preponderance of the evidence the necessary factual predicate for a § 3C1.1 adjustment. We do not say that it would not have been preferable for the government to have provided the court with additional evidence, as Johnson proposes. But given the deferential standard of review in this case (and being in any event in agreement with the District Court’s finding that the letter constituted an attempt to suborn perjury), we see no basis for reversal.
Johnson’s sentence is affirmed and his pro se motion for Leave to File Deposition is denied.
. The Honorable Nanette K. Laughrey, United States District Judge for the Western District of Missouri.
. A second count in the indictment, for possession of cocaine, was dropped.
. The court nevertheless adjusted Johnson's base offense level downward by three levels for acceptance of responsibility.
. A copy of the original letter is not in the designated record on appeal or in the Joint Appendix. The text of the letter (copied accurately, we assume, since neither of the parties has indicated otherwise) appears in paragraph 15 of the Presentence Investigation Report (PSR) prepared by the probation office. Because we do not have a copy of the original letter, we will quote it here exactly as it appears in the PSR, without ourselves noting errors or emphasis.