We agree with defendant-appellant that the district court erred in denying his 28 U.S.C. Sec. 2255 motion to vacate. The motion raised the issue of whether the federal district court had failed to comply with provisions of Rule 11, Fed.R.Crim.P., in accepting defendant's plea of guilty to second degree murder pursuant to which he was given a 20-year sentence. Defendant, then a federal prison inmate, was indicted under 18 U.S.C. Sec. 1111 on a charge of first degree murder in connection with the knife killing of another prisoner in a scuffle. He entered a plea of not guilty. On February 4, 1969 after a jury was empaneled, he withdrew the plea and entered a plea of guilty of second degree murder.

The defendant had received a mental examination pursuant to 18 U.S.C. Sec. 4244. The resulting report to the court stated that he was a "borderline mentally deficient," with a chronological age of 24 but a mental age of 12 and an I.Q. of 76. The record reveals that he had a second grade education and could not read.

Rule 11 provides that the court shall not accept a plea of guilty "without first addressing the defendant personally and determining that the plea is made voluntarily with understanding of the nature of the charge and the consequences of the plea." Initially the proceedings were directed toward this requirement. We set out in the margin what occurred that might tend to show the defendant's understanding of the nature of the charge.1 This simply does not rise to the level of the court's personally addressing the defendant and determining that he understands the nature of the charge. Significantly, in its brief the government does not seriously address itself to this mandate of the Rule but emphasizes alleged compliance with the last sentence of Rule 11, which provides that the court not enter a judgment upon a plea of guilty "unless it is satisfied that there is a factual basis for the plea."2 This defendant's plea having been entered, the court proceeded to inquire into the factual basis. The events then and subsequently occurring underscore our conclusion concerning lack of understanding of the charge.3 The United States Attorney recited to the court facts which could have been the basis for either second degree murder or for manslaughter, and defendant confirmed the statement of facts as correct. Next, defense counsel addressed the court and recited facts which tended to show that the scuffle occurred when the victim "came at" defendant after defendant had broken off a verbal encounter with the victim and walked away. Those facts would have supported guilt of second degree murder, of manslaughter, or a valid defense of self defense. The puzzling state in which this left the matter was pointed up by the colloquy which followed:

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THE COURT: Is this a suggestion that the plea he has just entered should be withdrawn?

MR. WADSWORTH: No sir, it is not. It is just things about him that I wanted you to know about which would have been a jury question. I just wanted you to know about them.

THE COURT: Monroe, do you know what you are doing?

DEFENDANT MONROE: Yes sir.

THE COURT: Monroe, how long have you had that knife?

DEFENDANT MONROE: Not long, about five days.

The court then indicated it would not accept the plea if there were any suggestion that defendant did not intend to kill the victim. Counsel responded "Your Honor, it is his intention to plead guilty as set forth," and, "Let the record show that he be found guilty based on the facts related." The court than interrogated defense counsel concerning intent, to which counsel replied that there was evidence of intent in the form of the defendant's having dug up his knife from where it was buried and of previous animosity between defendant and victim.4 In summary, it appears that the thrust of inquiry at the proceeding was almost solely in the direction of whether the statements made by the prosecutor and the defense counsel were sufficiently complete and consistent to meet the requirement of a factual basis for a plea and not upon what the defendant understood concerning the charge.5 In such a context, and in the absence of any explanation shown to have been given to him of what constituted second degree murder, and of the possibility of manslaughter and of self defense, it cannot be inferred that this defendant, "borderline mentally deficient" with a mental age of 12 and unable to read, had sufficient understanding of the charge for his plea to be valid. While the trial court need not follow any particular ritual, a routine boilerplate question to the defendant as to whether he understands the charges is not sufficient, and a single response by the defendant that he "understands" the charge "gives no assurance or basis for believing he does." Dorrough v. United States, 385 F.2d 887, 890 (5th Cir.1967), rehearing denied, 397 F.2d 811, cert. denied, 394 U.S. 1019, 89 S. Ct. 1637, 23 L. Ed. 2d 44 (1969). The affirmative responses of defendant and his counsel to the court's inquiries whether defendant understood the charge are not a substitute for knowledge.

Rule 11 has a two-fold purpose. It is designed to assist the trial judge in making the constitutionally required determination that the plea is voluntary. And it is intended to make a complete record at the time the plea is entered of the factors relevant to the voluntariness determination, eliminating any need to resort to later fact finding procedures in a highly subjective area. McCarthy v. United States, 394 U.S. 459, 465, 469-470, 89 S. Ct. 1166, 22 L. Ed. 2d 418, 424, 427 (Apr. 2, 1969). Meticulous adherence to the rule tends to discourage, and to enable expeditious disposition of, frivolous post-conviction attacks on pleas of guilty, and both of these goals are undermined to the extent the judge relies upon assumptions not based upon recorded inquiries made by him. Id. at 465, 467, 89 S. Ct. 1166, 22 L.Ed.2d at 425, 426.

[W]here the charge encompasses lesser included offenses, personally addressing the defendant as to his understanding of the essential elements of the charge to which he pleads guilty would seem a necessary prerequisite to a determination that he understands the meaning of the charge. In all such inquiries, "[m]atters of reality, and not mere ritual, should be controlling." Kennedy v. United States, 397 F.2d 16, 17 (CA6th Cir. 1968).

Id. at 467-468 n. 20, 89 S. Ct. at 1171, 22 L.Ed.2d at 426 n.20. In this instance the plea was entered a few months prior to McCarthy, and the "automatic prejudice" rule of that case is not available to defendant, Barton v. United States, 458 F.2d 537 (5th Cir., 1972), but a pre-McCarthy plea may be attacked as to voluntariness, and when it can be shown that the plea was not voluntarily and understandingly entered it must be invalidated. Id. Rule 11 is not constitutionally mandated but assists the judge in making the constitutionally required determination of true voluntariness, and the 1966 amendment to the Rule (adding the provision expressly requiring the court to address the defendant personally) furthers the purpose of better ability of the judge to ascertain the plea's voluntariness (as well as the purpose of developing a better record). McCarthy v. U. S., supra, 394 U.S. at 465-466, 89 S. Ct. 1166, 22 L.Ed.2d at 425. Sufficient understanding of the charge, on the basis of which to make an informed decision concerning a plea, is a part of the concept of voluntariness. Entry of a plea waives several constitutional rights (including privilege against self incrimination, trial by jury, and confrontation), and to be valid the waiver must be of a known right or privilege, and moreover, since a guilty plea admits all elements of a criminal charge, it cannot be truly voluntary unless the defendant possesses understanding of the law as well as the facts. Id. at 466, 89 S. Ct. 1166, 22 L. Ed.2d at 425. Therefore, in a pre-McCarthy plea, the absence of the court's directly addressing the accused, while not necessarily alone a fatal defect, is evidentiary on the issue of voluntariness.

On the facts and circumstances of this case we conclude that the plea of guilty did not come up to constitutional standards of voluntariness.

Vacated and remanded.