Opinion of the Court.
EFFRON, Judge:A general court-martial composed of officer and enlisted members convicted appellant, contrary to his pleas, of drunken and reckless operation of a vehicle and negligent homicide,1 in violation of Articles 111 and 134, Uniform Code of Military Justice, 10 USC §§ 911 and 934, respectively. Appellant was sentenced to a dishonorable discharge, confinement for 3 years, and total forfeitures. The convening authority approved the sentence as adjudged. The Court of Criminal Appeals affirmed. 45 MJ 613 (1997).
*99On appellant’s petition, we granted review of the following issues:
I
WHETHER APPELLANT WAS DENIED EFFECTIVE ASSISTANCE OF COUNSEL WHEN COUNSEL FAILED TO INTRODUCE CLEARLY EXCULPATORY EVIDENCE FROM AN ACCIDENT RECONSTRUCTION EXPERT WHERE THE ACCIDENT RECONSTRUCTION WAS COMPLETED PRIOR TO TRIAL, THE EXPERT WAS PREPARED TO TESTIFY, THIS EVIDENCE WAS THE ONLY DIRECT EVIDENCE SUPPORTING THE DEFENSE THEORY, AND APPELLANT FULLY EXPECTED THE EXPERT TO TESTIFY.
II
WHETHER THE ARMY COURT OF CRIMINAL APPEALS ERRED AS A MATTER OF LAW BY FAILING TO ORDER AFFIDAVITS AS REQUESTED BY THE DEFENSE AFTER THE DEFENSE MADE A PRIMA FACIE CASE THAT THE TRIAL DEFENSE COUNSEL WERE INEFFECTIVE, RULING INSTEAD THAT AN APPELLANT MUST EFFECTIVELY PERFECT A CASE OF INEFFECTIVE ASSISTANCE OF COUNSEL BEFORE THE COURT WILL EXERCISE ITS POWER TO FIND FACTS FOR INEFFECTIVE ASSISTANCE OF COUNSEL CLAIMS PURSUANT TO UCMJ, ART. 66, 10 USC § 866 (1988) AND UNITED STATES V. LEWIS, 42 MJ 1 (1995).
We hold that appellant has met his threshold burden under Strickland v. Washington, 466 U.S. 668, 687-94, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984), and that the Court of Criminal Appeals erred when it dismissed appellant’s claim of ineffective assistance of counsel without developing a sufficient record.
FACTS
Appellant was convicted of drunk and reckless driving and negligent homicide, following an early morning car accident that resulted in the death of Specialist (SPC) McLean. SPC McLean was struck by appellant’s car while he was participating in a group road march, and he died from his wounds shortly thereafter.
At trial, Staff Sergeant (SSG) Johnson testified that appellant had been driving fast and “swerving across the road” prior to the accident and that the car had swerved “ ‘completely off the right side of road” before it struck SPC McLean. SSG Johnson also testified that the marchers were wearing chemical lights and were visible to oncoming traffic. One of the road marchers and the noncommissioned officer in charge of the march testified that SPC McLean was wearing the proper reflective attire. Sergeant (SGT) Hill, the military policeman who investigated this accident, opined that the collision occurred “off the road way, on the right shoulder.” The Government also introduced evidence that appellant’s blood-alcohol concentration at the time of the accident was .16 to .17, and an expert witness testified as to the relationship between this level of intoxication and impairment.
The defense’s theory of the case was that appellant was neither impaired by alcohol at the time of the accident nor negligent in his operation of his vehicle. Specifically, the defense argued that: (1) appellant’s actions were within the normal range of expected reactions; and (2) SPC McLean was walking on the roadway, on the wrong side of the road, when the accident occurred, and he was not visible to appellant because it was dark and he was wearing camouflage without proper reflective gear.
To provide a factual basis for their arguments, the defense retained an accident reconstruction expert, Mr. Edward Livesay, who prepared a report based on the data collected during the military police investigation. Mr. Livesay assumed that both appellant’s car and SPC McLean’s body traveled in straight lines following impact and concluded that SPC McLean was on the roadway when he was struck by appellant’s car. In addition, Mr. Livesay opined that SPC McLean would not have been visible to appellant and that appellant’s reaction time was *100within the normal range of expected reaction times, which indicated that appellant was not impaired at the time of the accident. Defense counsel, however, did not call Mr. Live-say to testify at appellant’s trial.
ANALYSIS
To establish ineffective assistance of counsel, appellant must show both: (1) that his trial defense “counsel’s performance was deficient,” prior i.e., that counsel’s error in failing to call Mr. Livesay as a witness was “so serious that [they were] not functioning as the ‘counsel’ guaranteed [appellant] by the Sixth Amendment”; and (2) that “the deficient performance prejudiced the defensef,]” ie., that the error was “so serious as to deprive [appellant] of a fair trial, a trial whose result is reliable.” Strickland, supra at 687, 104 S.Ct. 2052. Because counsel is presumed to have performed competently, id. at 689, 104 S.Ct. 2052, an appellant asserting an ineffective-assistance claim “must surmount a very high hurdle.” United States v. Moulton, 47 MJ 227, 229 (1997), cert. denied, — U.S. —, 118 S.Ct. 1048, 140 L.Ed.2d 112 (1998).
Appellant argues that failure of his trial defense counsel to call Mr. Livesay to testify at trial rendered their performance ineffective. Appellant asserts that “Mr. Livesay’s report contained a wealth of potentially exculpatory information,” Final Brief at 7, and “provided the most credible, compelling evidence corroborating appellant’s version of the car accident.” According to appellant, Mr. Livesay’s testimony “would have speared the heart of the Government’s case” and made the defense case at the same time, Final Brief at 4, and “[n]o possible strategy decision could justify the failure to use this evidence.” Final Brief at 7.
Appellant also asserts that, at a minimum, his evidence establishes a “prima facie ” case of ineffective assistance of counsel and that the Court of Criminal Appeals could not resolve his claim against him without a sufficient evidentiary foundation. Under those circumstances, according to appellant, the Court of Criminal Appeals erred by dismissing his ineffective-assistance claim without requiring trial defense counsel to explain their decision.
The Government replies that: (1) the decision not to call Mr. Livesay was a tactical decision of counsel; and (2) even if the performance of trial defense counsel was deficient in this regard, appellant was not prejudiced because Mr. Livesay’s conclusions were used by trial defense counsel in their cross-examination of the Government’s witnesses.
Notwithstanding the high hurdle appellant must surmount to succeed ultimately on the merits of his claim, at this point we need only decide whether appellant has “met the threshold burden to demonstrate that his trial lawyer’s performance was ineffective,” United States v. Ingham, 42 MJ 218, 224 (1995), cert. denied, 516 U.S. 1063, 116 S.Ct. 745, 133 L.Ed.2d 693 (1996). In that context, we ask whether appellant’s assertions, if left unrebutted, would meet the Strickland standard and appellant would be entitled to relief as a matter of law, such that the Government must respond to his allegations. United States v. Lewis, 42 MJ 1, 6 (1995).
We believe that appellant has made the required showing. He has submitted an affidavit from Mr. Livesay in which Mr. Livesay states that he “expected” and was prepared to testify at appellant’s trial. As to the content of his testimony, Mr. Livesay states that he would have sworn “to the facts and opinions that are contained in [his] report,” testifying about the preparation and content of his report and his conclusions about the causes of the accident. Appellant also has submitted his own affidavit in which he states that he “expected Mr. Livesay to testify” at trial and expected his report to be presented to the members.
The Government’s case against appellant relied heavily on the testimony of SGT Hill, the military’s accident reconstruction expert. Although SSG Johnson was driving behind appellant prior to the accident, neither she nor the road marcher who testified at appellant’s trial actually witnessed the impact. Trial defense counsel contested the Government’s version of the events and attempted to offer appellant’s explanation of the acci*101dent, but they presented no affirmative evidence to support appellant’s theory.
In these circumstances, which would have presented a classic battle of experts, the potential damage to the side whose expert is missing can be devastating. Although trial defense counsel may have had valid reasons for deciding not to call Mr. Livesay to testify, those reasons are not apparent from the record, and it is not the province of this Court to speculate as to what those reasons might have been.
The deficiencies that have led us to dismiss other ineffective-assistance claims are not present in this case. Having submitted the content of the witness’s testimony and the witness’s statement that he was prepared to testify, appellant has “demonstrat[ed] that [a] specific individúale ] would have provided the court with specific testimony.” Moulton, supra at 229. If the record is developed and shows that trial defense counsel did not have a reasonable explanation for not calling Mr. Livesay to testify, then appellant will have established deficient performance. Under the circumstances of this case, there is at least a reasonable likelihood that, upon further review, appellant will be able to show that such a deficiency was prejudicial to his defense at trial. Appellant’s “allegation[s] and the record contain evidence which, if unrebutted, would overcome the presumption of competence.” Lewis, supra at 6. Because appellant met his “threshold burden” to establish ineffective assistance, the Court of Criminal Appeals could not decide his claim without developing an appropriate record on the matter. See Ingham, 42 MJ at 224; cf. United States v. Ginn, 47 MJ 236, 248 (1997).
DECISION
The decision of the United States Army Court of Criminal Appeals is set aside, and the record of trial is returned to the Judge Advocate General of the Army for remand to that court to develop the record as necessary to resolve appellant’s claim of ineffective assistance of counsel, by ordering affidavits from appellant’s trial defense counsel and, if necessary, by ordering a hearing under United States v. DuBay, 17 USCMA 147, 37 CMR 411 (1967).
Judges SULLIVAN and GIERKE concur.. Appellant was charged with involuntary manslaughter, in violation of Article 119, UCMJ, 10 USC § 919, but convicted of the lesser-included offense of negligent homicide.