Opinion by Judge Wesley.

"Buy-and-bust" cases often involve the testimony of an undercover officer. When the People can establish an overriding interest that open-court testimony by an undercover officer would jeopardize the officer's safety, the Trial Judge may close the courtroom during the testimony of that witness. For the reasons that follow, we conclude that the posting of a court officer outside the courtroom as a screening device under the circumstances of this case amounts to an "alternative to closure" that implicated defendant's Sixth Amendment right to a public trial. Because the "overriding interest" test ofWaller v. Georgia ( 467 U.S. 39) was satisfied, the order of the Appellate Division should be affirmed (see, People v. Ramos, 90 N.Y.2d 490, 497-499, cert denied 522 U.S. 1002).

Based on the allegations of undercover officer number 1625, defendant Michael Jones and codefendant Derrick Hudson were arrested on June 1, 1996, and charged with sale and possession of crack-cocaine in Brooklyn. At trial, the People moved to close the courtroom during the undercover's testimony. The court conducted a hearing pursuant to People v. Hinton ( 31 N.Y.2d 71, cert denied 410 U.S. 911) to determine the propriety of closure. The undercover testified that she had worked as an undercover officer for "[a] little less than three years," had made "[a]bout 250" drug purchases during that period, and had testified nine times at trial. At various times during those three years, she had worked as an undercover officer in Brooklyn. Approximately one month before defendant's trial, however, she had been transferred to Manhattan, and was working undercover for the "North Manhattan Initiative" at the time of the trial. The undercover stated that although she no longer worked in Brooklyn the possibility remained that she would at some point return there to operate as an undercover. She indicated that in her ongoing cases before the Brooklyn Grand Jury, she took precautions — such as not mingling with the general public, dressing in civilian garb, not traveling in a police vehicle and using a separate entrance to enter the courtroom — to protect her undercover status. The undercover also testified that she had about 10 "lost subjects" in Brooklyn who had not yet been arrested and that she had received threats in the past.

Following the Hinton hearing, the prosecution argued that it was not asking for the courtroom to be sealed. However, because a "probability" existed that the undercover officer would be sent back to Brooklyn and because codefendant Derrick Hudson was at large and subject to a bench warrant, the prosecution requested that, during the undercover's testimony, the court post a court officer outside the courtroom to question anyone who might pose a threat to her. Defense counsel objected, arguing there was no danger in having the undercover officer testify in open court as she no longer worked in Brooklyn.

The court determined that the closure request was premised on an overriding interest because the codefendant was still at large and had been bench warranted. The court concluded, however, that because the undercover would not be returning to the Brooklyn area, complete closure of the courtroom during her testimony was not warranted. The court decided to post a court officer outside the courtroom door during the undercover's testimony and to allow admission of attorneys and all family members of defendant. The court officer was asked to interview all other people seeking entry to the courtroom and instructed to ask attendees their identity and their interest in coming to court. The court further stated that, if necessary, it would recess proceedings to determine whether an individual should be admitted.

After the undercover testified, the prosecutor noted on the record, without objection from defense counsel, that only three individuals were present in the courtroom during the course of the undercover's testimony — an attorney from defense counsel's office, another prosecutor from the District Attorney's office, and a member of defendant's family. The prosecution also noted that the court officer stationed outside the courtroom had reported that "at no time did anyone else seek to enter the courtroom and everyone who sought entrance was permitted in." Defendant was convicted of criminal sale of a controlled substance in the third degree.

The Appellate Division rejected defendant's contention that the posting of a court officer outside the courtroom to screen potential spectators abridged his Sixth Amendment right to a public trial ( 266 A.D.2d 476). We now affirm.

Although a criminal defendant has a right to a public trial (see, US Const, 6th Amend), that right is not absolute (see, People v. Ramos, 90 N.Y.2d 490, 497, supra). Trial courts have the discretion to exclude the public, although they must exercise that discretion "`sparingly * * * and then, only when unusual circumstances necessitate it'" (People v. Martinez, 82 N.Y.2d 436, 441 [quoting People v. Hinton, 31 N.Y.2d 71, 76, supra]). "Closure remains only an exception to the mandatory postulate of open trials" (People v. Kin Kan, 78 N.Y.2d 54, 57, rearg denied 78 N.Y.2d 1008; see also, Press-Enterprise Co. v. Superior Ct. of Cal., 464 U.S. 501, 509 ["Closed proceedings, although not absolutely precluded, must be rare and only for cause shown that outweighs the value of openness"]; Globe Newspaper Co. v. Superior Ct. for the County of Norfolk, 457 U.S. 596, 606 ["the State's justification in denying access must be a weighty one"]; Richmond Newspapers, Inc. v. Commonwealth of Va., 448 U.S. 555, 581 ["Absent an overriding interest * * * the trial of a criminal case must be open to the public"]).

The determination whether the right to an open trial will give way to other rights or interests requires a careful balancing of those concerns (Waller v. Georgia, 467 U.S. 39, 45, supra; see also, People v. Nieves, 90 N.Y.2d 426, 429; People v. Kin Kan, supra, 78 N.Y.2d, at 57). To assist courts in striking this balance, the United States Supreme Court has established a four-part standard the closure order must satisfy to survive Sixth Amendment scrutiny:

"[T]he party seeking to close the hearing must advance an overriding interest that is likely to be prejudiced, the closure must be no broader than necessary to protect that interest, the trial court must consider reasonable alternatives to closing the proceeding, and it must make findings adequate to support the closure"

(Waller, supra, 467 US, at 48).

The proponent of closure must first assert that a substantial probability of prejudice to a compelling interest will result from an open proceeding (Press-Enterprise Co. v. Superior Ct. of Cal., 478 U.S. 1, 14;see also, People v. Ramos, supra, 90 N.Y.2d, at 498). Thus, a nexus between the particular overriding interest asserted and open-court testimony must be established in any given case (People v. Ramos, supra, 90 N.Y.2d, at 498). A defendant's Sixth Amendment rights "must not be lightly cast aside simply because the People claim that an undercover officer's safety or effectiveness is at risk" and we have stressed that trial courts must "vigilantly ensure that Waller's demanding first prong is satisfied before closing a courtroom" (id., at 506). When closure is sought for the safety of undercover law enforcement officers, we have held that "the mere possibility that this safety interest might be compromised by open-court testimony does not justify abridgement of a defendant's constitutional right to a public trial" (id., at 498 [emphasis added]; see also, People v. Martinez, supra, 82 N.Y.2d, at 443).

In the case at hand, the prosecution asked the court to post a court officer outside the courtroom to monitor those entering and exiting the courtroom. Defendant contends that the use of the screening mechanism employed here is tantamount to total closure of the courtroom. Total closure of a courtroom excludes all persons (other than court personnel, the witness, defendant and trial counsel) from the courtroom (see,Waller, supra, 467 US, at 42; see also, Press-Enterprise Co. v. Superior Ct. of Cal., 478 U.S. 1, supra [exclusion of the public from 41-day preliminary hearing]; Press-Enterprise Co. v. Superior Ct. of Cal., 464 U.S. 501, supra [exclusion of the public from six-weeks of voir dire proceedings]). A screening and identification procedure, by contrast, bars only those who do not submit to the identification or those who are "chilled" by the procedure itself (United States v. DeLuca, 137 F.3d 24, 33-34 [1st Cir], cert denied 525 U.S. 874; see also, United States v. Brazel, 102 F.3d 1120, 1155 [11th Cir], cert denied 522 U.S. 822).

The trial court's order did not exclude all members of the general public (cf., People v. Tolentino, 90 N.Y.2d 867; People v. Ramos, 90 N.Y.2d 490, supra; People v. Martinez, 82 N.Y.2d 436, supra), nor did it exclude any specific person (cf., People v. Nieves, 90 N.Y.2d 426,supra; People v. Kin Kan, 78 N.Y.2d 54, supra). Rather, the court reserved the right to exclude based on its own evaluation of the explanation offered by any individual seeking admission during only the undercover officer's testimony.

Some courts have considered such a screening mechanism to be "an alternative to closure" (see, e.g., People v. Smalls, 275 A.D.2d 645, lv denied 95 N.Y.2d 969; People v. Carillo, 267 A.D.2d 43; People v. Witt, 258 A.D.2d 300, lv denied 93 N.Y.2d 1029; People v. Torres, 257 A.D.2d 639,lv denied 93 N.Y.2d 858; People v. Perez, 245 A.D.2d 71, lv denied 91 N.Y.2d 976; People v. Brown, 243 A.D.2d 641, lv denied 91 N.Y.2d 924;see also, People v. Martinez, supra, 82 N.Y.2d, at 444). Others have referred to the screening procedure as a "partial" closure (see, United States v. DeLuca, supra, 137 F.3d, at 33; United States v. Brazel, supra, 102 F.3d, at 1155; Woods v. Kuhlmann, 977 F.2d 74, 76 [2d Cir]). Whatever we call it, the device implemented here raises the same secrecy and fairness concerns that a total closure does ( contra, Woods v. Kuhlmann, supra, 977 F.2d, at 76 ). The defendant's Sixth Amendment right to a public trial is still implicated (see id.). However, the question remains whether the People must establish an "overriding interest" when a court is asked to order a limited and conditional restriction on access to the courtroom? Because the Sixth Amendment is implicated by the procedure sought, the People must still meet the "overriding interest" requirement of Waller.

We are aware that some courts have recognized that a less demanding standard can be applied to limited closure requests (see, e.g., Woods v. Kuhlmann, supra, 977 F.2d, at 76 ["when a trial court orders a partial, as opposed to a total, closure of a court proceeding at the request of one party, a `substantial reason' rather than Waller's `overriding interest' will justify the closure"]; see also, United States v. Osborne, 68 F.3d 94, 98-99 [5th Cir]; United States v. Sherlock, 962 F.2d 1349, 1357 [9th Cir], cert denied 506 U.S. 958; Douglas v. Wainwright, 739 F.2d 531, 533 [11th Cir], cert denied 469 U.S. 1208). We disagree. We believe that there is no need to adopt such an articulation of the Waller standard since Waller already contemplates a balancing of competing interests in closure decisions. When the procedure requested impacts on a defendant's right to a public trial, nothing less than an overriding interest can satisfy constitutional scrutiny (see, Waller v. Georgia, supra, 467 US, at 48). As the United States Supreme Court has recognized, "[t]he presumption of openness may be overcome only by an overriding interest based on findings that closure is essential to preserve higher values and is narrowly tailored to serve that interest" (Press-Enterprise Co. v. Superior Ct. of Cal., 464 U.S. 501, 510, supra [emphasis added]).

The proponent of closure must still establish that there is a "substantial probability" that the overriding interest asserted will be prejudiced as a result of an open proceeding (People v. Ramos, 90 N.Y.2d 490, 498-499, supra). Trial courts are called upon to ensure that the closure is no broader than necessary and to consider alternatives to closure suggested by the parties. The breadth of the closure request therefore will always be measured against the risk of prejudice to the asserted overriding interest. The risk of prejudice to a compelling interest such as the safety of an undercover officer depends upon the facts of each case. For example, in Ramos and Martinez the proof concerning the risks of prejudice to the undercover officers' open court testimony required different, yet appropriate, closure results (compare,People v. Ramos, 90 N.Y.2d 490, supra, with People v. Martinez, 89 N.Y.2d 436, supra). This part of the balancing test embraces consideration of measures less than complete closure while preserving the defendant's right to an open trial.

Here, the People met their burden. The codefendant was at large and a bench warrant had been issued for his arrest. In addition, while the undercover testified that she no longer worked in Brooklyn, she still had occasion to return to there to testify before the Grand Jury and there were still 10 "lost subjects" who had yet to be arrested (see, People v. Diaz, 237 A.D.2d 457, lv denied 90 N.Y.2d 892; see also, People v. Ramos, supra, 90 N.Y.2d, at 499). The undercover also testified as to threats she had received, although none were particularly related to the instant case (see, People v. Martinez, supra, 82 N.Y.2d, at 443). Furthermore, the People's application was limited in scope and was narrowly tailored to that portion of the trial that might jeopardize the undercover's safety (People v. Ramos, supra, 90 N.Y.2d, at 504). As a final matter, we note that when the alternative to closure was sought by the prosecution, at no time did defendant argue that there was a less restrictive alternative to posting a guard outside the courtroom. Certainly, "[i]f, at that point, the defendant had alternative measures in mind that he wished the court to consider, he had `the responsibility of showing to the court's satisfaction that [they] would eliminate the dangers shown'" (id., at 505 [citation omitted]). Thus, all four Waller prongs have been satisfied and the restriction on the public's access to the courtroom in this case did not constitute a violation of defendant's right to a public trial.

Accordingly, the order of the Appellate Division should be affirmed.

Order affirmed.