Opinion of the Court by
Mr. Justice Stewart,
announced by Mr. Justice Fortas.
In Pointer v. Texas, 380 U. S. 400, 403, this Court held that the Sixth Amendment right of an accused to confront the witnesses against him is a “fundamental right . . . made obligatory on the States by the Fourteenth Amendment.” The question presented in this case is whether Illinois denied that right to the petitioner, Fleming Smith. He was convicted in a criminal court of Cook County, Illinois, upon a charge of illegal sale of narcotics, and his conviction was affirmed on appeal. We granted certiorari to consider his constitutional claim.
At the trial the principal witness against the petitioner was a man who identified himself on direct examination as “James Jordan.” This witness testified that he had purchased a bag of heroin from the petitioner in a restaurant with marked money provided by two Chicago police officers. The officers corroborated part of this testimony, but only this witness and the petitioner testified to the crucial events inside the restaurant, and the petitioner’s version of those events was entirely different. The only real question at the trial, therefore, was the relative credibility of the petitioner and this prosecution witness.
On cross-examination this witness was asked whether “James Jordan” was his real name. He admitted, over the prosecutor’s objection, that it was not. He was then asked what his correct name was, and the court sustained the prosecutor’s objection to the question. Later the witness was asked where he lived, and again the court sustained the prosecutor’s objection to the question.'
As the Court said in Pointer, “It cannot seriously be doubted at this late date that the right of cross-examination is included in the right of an accused in a criminal case to confront the witnesses against him.” 380 U. S., at 404. Even more recently we have repeated that “a denial of cross-examination without waiver . . . would be constitutional error of the first magnitude and no amount of showing of want of prejudice would cure it.” Brookhart v. Jams, 384 U. S. 1, 3.
In the present case there was not, to be sure, a complete denial of all right of cross-examination. But the petitioner was denied the right to ask the principal prosecution witness either his name or where he lived, although the witness admitted that the name he had first given was false. Yet when the credibility of a witness is in issue, the very starting point in “exposing falsehood and bringing out the truth” through cross-examination must necessarily be to ask the witness who he is and where he lives. The witness’ name and address open countless avenues of in-court examination and out-of-court investigation. To forbid this most rudimentary inquiry at the threshold is effectively to emasculate the right of cross-examination itself.
In Alford v. United States, 282 U. S. 687, this Court almost 40 years ago unanimously reversed a federal conviction because the trial judge had sustained objections to questions by the defense seeking to elicit the “place of residence” of a prosecution witness over the insistence of defense counsel that “the jury was entitled to know 'who the witness is, where he lives and what his business is.’ ” 282 U. S., at 688-689. What the Court said in reversing that conviction is fully applicable here:
“It is the essence of a fair trial that reasonable latitude be given the cross-examiner, even though he is unable to state to the court what facts a reasonable cross-examination might develop. Prejudice ensues from a denial of the opportunity to place the witness in his proper setting and put the weight of his testimony and his credibility to a test, without which the jury cannot fairly appraise them. ... To say that prejudice can be established only by showing that the cross-examination, if pursued, would necessarily have brought out facts tending to discredit the testimony in chief, is to deny a substantial right and withdraw one of the safeguards essential to a fair trial. . . .
"... The question 'Where do you live?’ was not only an appropriate preliminary to the cross-examination of the witness, but on its face, without any such declaration of purpose as was made by counsel here, was an essential step in identifying the witness with his environment, to which cross-examination may always be directed. . . .
“The extent of cross-examination with respect to an appropriate subject of inquiry is within the sound discretion of the trial court. It may exercise a reasonable judgment in determining when the subject is exhausted. . . . But no obligation is imposed on the court, such as that suggested below, to protect a witness from being discredited on cross-examination, short of an attempted invasion of his constitutional protection from self incrimination, properly invoked. There is a duty to protect him from questions which go beyond the bounds of proper cross-examination merely to harass, annoy or humiliate him. . . . But no such case is presented here. . . 282 U. S., at 692-694.
In Pointer v. Texas, supra, the Court made clear that “the right of an accused to be confronted with the witnesses against him must be determined by the same standards whether the right is denied in a federal or state proceeding.” 380 U. S., at 407-408. In this state case we follow the standard of Alford and hold that the petitioner was deprived of a right guaranteed to him under the Sixth and Fourteenth Amendments of the Constitution.
D , Reversed.
70 Ill. App. 2d 289, 217 N. E. 2d 546.
387 U. S. 904.
The officers testified that the witness had entered the restaurant with the marked money and without narcotics, and that he had emerged with a bag of heroin. They also testified that they had found some of the marked money in the petitioner’s possession when they arrested him.
The petitioner testified that he had refused to sell the witness narcotics but had directed him to another man in the restaurant from whom he believed a purchase had been made. The petitioner also testified that he used a $5 bill to purchase a cup of coffee, and must have received the marked money in his change.
“MR. PRide: Is James Jordan your correct name?
“Mr. Martwick: Object.
“Mr. Pride.* I have a right to know if it is his correct name.
“The Court: He may answer if it is his correct name or not.
“Mr. Pride: Is that your correct name?
“A. No, it is not.
“Q. What is your correct name?
“Mr. Martwick: Object.
“The Court: I won’t have him answer that.”
“Q. Now, where do you live now?
“Mr. Martwick: Objection.
“Mr. Pride: This is material.
“Mr. Martwick: Objection, Judge.
“The Court: Yes, objection allowed.”
The record shows that in fact the petitioner and his lawyer knew “Jordan” and that the lawyer had once represented him. However, there is no evidence in the record that either the petitioner or his lawyer knew “Jordan’s” correct name or where he was living at the time of this trial.
See Pointer v. Texas, 380 U. S., at 404.
It is to be noted that no claim of the privilege against compulsory self-incrimination was asserted by “James Jordan.” Cf. United States v. Cardillo, 316 F. 2d 606. Nor are this Court’s decisions in McCray v. Illinois, 386 U. S. 300, and Roviaro v. United States, 353 U. S. 53, relevant here. In neither of those cases was the informer a witness for the prosecution. Another recent Illinois decision seems to have recognized that the state evidentiary informer privilege is not involved when the informer is himself a witness at the trial. People v. Smith, 69 Ill. App. 2d 83, 89, 216 N. E. 2d 520, 523. See 8 Wigmore, Evidence §2374, n. 6 (McNaughton rev. 1961).