(Slip Opinion) OCTOBER TERM, 2005 1 

Syllabus 

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is

being done in connection with this case, at the time the opinion is issued.

The syllabus constitutes no part of the opinion of the Court but has been

prepared by the Reporter of Decisions for the convenience of the reader. 

See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337. 

SUPREME COURT OF THE UNITED STATES 

Syllabus 

HOLMES v. SOUTH CAROLINA 

CERTIORARI TO THE SUPREME COURT OF SOUTH CAROLINA 

No. 04–1327. Argued February 22, 2006—Decided May 1, 2006 

At petitioner’s South Carolina trial for murder and related crimes, the 

prosecution relied heavily on forensic evidence that strongly supported petitioner’s guilt. Petitioner sought to undermine the State’s 

forensic evidence by introducing expert testimony suggesting that the

evidence had been contaminated and that the police had engaged in a

plot to frame him. Petitioner also sought to introduce evidence that 

another man, Jimmy McCaw White, had been in the victim’s 

neighborhood on the morning of the assault and that White had either acknowledged petitioner’s innocence or admitted to committing

the crimes himself. In White’s pretrial testimony, he denied making

the incriminating statements and provided an alibi for the time of the 

assault. 

The trial court excluded petitioner’s third-party guilt evidence citing the State Supreme Court’s Gregory decision, which held such evidence admissible if it raises a reasonable inference as to the defendant’s own innocence, but inadmissible if it merely casts a bare 

suspicion or raises a conjectural inference as to another’s guilt. Affirming the trial court, the State Supreme Court cited both Gregory

and its later decision in Gay, and held that where there is strong forensic evidence of an appellant’s guilt, proffered evidence about a 

third party’s alleged guilt does not raise a reasonable inference as to 

the appellant’s own innocence. Applying this standard, the court

held that petitioner could not overcome the forensic evidence against 

him. 

Held: A criminal defendant’s federal constitutional rights are violated

by an evidence rule under which the defendant may not introduce

evidence of third-party guilt if the prosecution has introduced forensic evidence that, if believed, strongly supports a guilty verdict.

“[S]tate and federal rulemakers have broad latitude under the Con-
2 HOLMES v. SOUTH CAROLINA 

Syllabus 

stitution to establish rules excluding evidence from criminal trials.” 

United States v. Scheffer, 523 U. S. 303, 308. This latitude, however, 

has limits. “Whether rooted directly in the Due Process Clause of the 

Fourteenth Amendment or in the Compulsory Process or Confrontation clauses of the Sixth Amendment, the Constitution guarantees

criminal defendants ‘a meaningful opportunity to present a complete

defense.’ ” Crane v. Kentucky, 476 U. S. 683, 690. This right is 

abridged by evidence rules that “infring[e] upon a weighty interest of

the accused” and are “ ‘arbitrary’ or ‘disproportionate to the purposes

they are designed to serve.’ ” Scheffer, supra, at 308. 

While the Constitution thus prohibits the exclusion of defense evidence under rules that serve no legitimate purpose or that are disproportionate to the ends that they are asserted to promote, wellestablished rules of evidence permit trial judges to exclude evidence if 

its probative value is outweighed by certain other factors such as unfair prejudice, confusion of the issues, or potential to mislead the

jury. An application of this principle is found in rules regulating the 

admission of evidence proffered by criminal defendants to show that 

someone else committed the crime with which they are charged.

Such rules are widely accepted and are not challenged here. 

 In Gregory, the South Carolina Supreme Court adopted and applied a rule intended to be of this type. In Gay and this case, however, that court radically changed and extended the Gregory rule by

holding that, where there is strong evidence of a defendant’s guilt, 

especially strong forensic evidence, proffered evidence about a third

party’s alleged guilt may (or perhaps must) be excluded. Under this 

rule, the trial judge does not focus on the probative value or the potential adverse effects of admitting the defense evidence of thirdparty guilt. Instead, the critical inquiry concerns the strength of the 

prosecution’s case: If the prosecution’s case is strong enough, the evidence of third-party guilt is excluded even if that evidence, if viewed 

independently, would have great probative value and even if it would 

not pose an undue risk of harassment, prejudice, or confusion of the 

issues. Furthermore, as applied below, the rule seems to call for little, if any, examination of the credibility of the prosecution’s witnesses or the reliability of its evidence. 

By evaluating the strength of only one party’s evidence, no logical 

conclusion can be reached regarding the strength of contrary evidence offered by the other side to rebut or cast doubt. Because the 

rule applied below did not heed this point, the rule is “arbitrary” in

the sense that it does not rationally serve the end that the Gregory

rule and other similar third-party guilt rules were designed to further. Nor has the State identified any other legitimate end served by 
Cite as: 547 U. S. ____ (2006) 3 

Syllabus 

the rule. Thus, the rule violates a criminal defendant’s right to have 

“ ‘a meaningful opportunity to present a complete defense.’ ” Crane, 

supra, at 690. Pp. 4–11. 

361 S. C. 333, 605 S. E. 2d 19, vacated and remanded. 

ALITO, J., delivered the opinion for a unanimous Court. 
_________________ 

_________________ 

Cite as: 547 U. S. ____ (2006) 1 

Opinion of the Court 

NOTICE: This opinion is subject to formal revision before publication in the

preliminary print of the United States Reports. Readers are requested to

notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order

that corrections may be made before the preliminary print goes to press. 

SUPREME COURT OF THE UNITED STATES 

No. 04–1327 

BOBBY LEE HOLMES, PETITIONER v. SOUTH 

CAROLINA

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF SOUTH 

CAROLINA 

[May 1, 2006]

 JUSTICE ALITO delivered the opinion of the Court. 

This case presents the question whether a criminal

defendant’s federal constitutional rights are violated by an

evidence rule under which the defendant may not introduce proof of third-party guilt if the prosecution has introduced forensic evidence that, if believed, strongly supports

a guilty verdict. 

I 

On the morning of December 31, 1989, 86-year-old Mary

Stewart was beaten, raped, and robbed in her home. She 

later died of complications stemming from her injuries. 

Petitioner was convicted by a South Carolina jury of murder, first-degree criminal sexual conduct, first-degree 

burglary, and robbery, and he was sentenced to death. 

State v. Holmes, 320 S. C. 259, 262, 464 S. E. 2d 334, 336 

(1995). The South Carolina Supreme Court affirmed his 

convictions and sentence, and this Court denied certiorari. 

Ibid., cert. denied, 517 U. S. 1248 (1996). Upon state postconviction review, however, petitioner was granted a new

trial. 361 S. C. 333, 335, n. 1, 605 S. E. 2d 19, 20, n. 1 

(2004). 
2 HOLMES v. SOUTH CAROLINA 

Opinion of the Court 

At the second trial, the prosecution relied heavily on the 

following forensic evidence: 

“(1) [Petitioner’s] palm print was found just above the

door knob on the interior side of the front door of the 

victim’s house; (2) fibers consistent with a black 

sweatshirt owned by [petitioner] were found on the

victim’s bed sheets; (3) matching blue fibers were 

found on the victim’s pink nightgown and on [petitioner’s] blue jeans; (4) microscopically consistent fibers were found on the pink nightgown and on [petitioner’s] underwear; (5) [petitioner’s] underwear 

contained a mixture of DNA from two individuals, and 

99.99% of the population other than [petitioner] and

the victim were excluded as contributors to that mixture; and (6) [petitioner’s] tank top was found to contain a mixture of [petitioner’s] blood and the victim’s

blood.” Id., at 343, 605 S. E. 2d, at 24. 

In addition, the prosecution introduced evidence that

petitioner had been seen near Stewart’s home within an

hour of the time when, according to the prosecution’s

evidence, the attack took place. Id., at 337–338, 343, 605 

S. E. 2d, at 21, 24. 

As a major part of his defense, petitioner attempted to

undermine the State’s forensic evidence by suggesting that 

it had been contaminated and that certain law enforcement officers had engaged in a plot to frame him. Id., at 

339, 605 S. E. 2d, at 22. Petitioner’s expert witnesses

criticized the procedures used by the police in handling the

fiber and DNA evidence and in collecting the fingerprint 

evidence. App. 299–311, 313–323. Another defense expert 

provided testimony that petitioner cited as supporting his 

claim that the palm print had been planted by the police. 

Id., at 326–327. 

Petitioner also sought to introduce proof that another

man, Jimmy McCaw White, had attacked Stewart. 361 
Cite as: 547 U. S. ____ (2006) 3 

Opinion of the Court 

S. C., at 340, 605 S. E. 2d, at 22. At a pretrial hearing,

petitioner proffered several witnesses who placed White in

the victim’s neighborhood on the morning of the assault, 

as well as four other witnesses who testified that White 

had either acknowledged that petitioner was “‘innocent’” 

or had actually admitted to committing the crimes. Id., at 

340–342, 605 S. E. 2d, at 22–23. One witness recounted 

that when he asked White about the “word . . . on the 

street” that White was responsible for Stewart’s murder,

White “put his head down and he raised his head back up 

and he said, well, you know I like older women.” App. 119.

According to this witness, White added that “he did what 

they say he did” and that he had “no regrets about it at 

all.” Id., at 120. Another witness, who had been incarcerated with White, testified that White had admitted to 

assaulting Stewart, that a police officer had asked the

witness to testify falsely against petitioner, and that 

employees of the prosecutor’s office, while soliciting the 

witness’ cooperation, had spoken of manufacturing evidence against petitioner. Id., at 38–50. White testified at 

the pretrial hearing and denied making the incriminating 

statements. 361 S. C., at 341–342, 605 S. E. 2d, at 23. He 

also provided an alibi for the time of the crime, but another witness refuted his alibi. Id., at 342, 605 S. E. 2d, at 

23. 

The trial court excluded petitioner’s third-party guilt

evidence citing State v. Gregory, 198 S. C. 98, 16 S. E. 2d 

532 (1941), which held that such evidence is admissible if it 

“‘raise[s] a reasonable inference or presumption as to [the

defendant’s] own innocence’” but is not admissible if it 

merely “‘cast[s] a bare suspicion upon another’” or “‘raise[s] 

a conjectural inference as to the commission of the crime by

another.’” App. 133–134 (quoting Gregory, supra, at 104, 

16 S. E. 2d, at 534). On appeal, the South Carolina Supreme Court found no error in the exclusion of petitioner’s

third-party guilt evidence. Citing both Gregory and its 
4 HOLMES v. SOUTH CAROLINA 

Opinion of the Court 

later decision in State v. Gay, 343 S. C. 543, 541 S. E. 2d 

541 (2001), the State Supreme Court held that “where there 

is strong evidence of an appellant’s guilt, especially where

there is strong forensic evidence, the proffered evidence 

about a third party’s alleged guilt does not raise a reasonable inference as to the appellant’s own innocence.” 361 

S. C., at 342–343, 605 S. E. 2d, at 24. Applying this standard, the court held that petitioner could not “overcome the

forensic evidence against him to raise a reasonable inference of his own innocence.” Id., at 343, 605 S. E. 2d, at 24. 

We granted certiorari. 545 U. S. ___ (2005). 

II 

“[S]tate and federal rulemakers have broad latitude

under the Constitution to establish rules excluding evidence from criminal trials.” United States v. Scheffer, 523 

U. S. 303, 308 (1998); see also Crane v. Kentucky, 476 U. S. 

683, 689–690 (1986); Marshall v. Lonberger, 459 U. S. 422, 

438, n. 6 (1983); Chambers v. Mississippi, 410 U. S. 284, 

302–303 (1973); Spencer v. Texas, 385 U. S. 554, 564 (1967).

This latitude, however, has limits. “Whether rooted directly in the Due Process Clause of the Fourteenth 

Amendment or in the Compulsory Process or Confrontation 

clauses of the Sixth Amendment, the Constitution guarantees criminal defendants ‘a meaningful opportunity to 

present a complete defense.’” Crane, supra, at 690 (quoting California v. Trombetta, 467 U. S. 479, 485 (1984); 

citations omitted). This right is abridged by evidence rules

that “infring[e] upon a weighty interest of the accused”

and are “‘arbitrary’ or ‘disproportionate to the purposes 

they are designed to serve.’” Scheffer, supra, at 308 (quoting Rock v. Arkansas, 483 U. S. 44, 58, 56 (1987)).

This Court’s cases contain several illustrations of “arbitrary” rules, i.e., rules that excluded important defense

evidence but that did not serve any legitimate interests. 

In Washington v. Texas, 388 U. S. 14 (1967), state statutes 
Cite as: 547 U. S. ____ (2006) 5 

Opinion of the Court 

barred a person who had been charged as a participant in 

a crime from testifying in defense of another alleged participant unless the witness had been acquitted. As a 

result, when the defendant in Washington was tried for 

murder, he was precluded from calling as a witness a

person who had been charged and previously convicted of

committing the same murder. Holding that the defendant’s right to put on a defense had been violated, we 

noted that the rule embodied in the statutes could not 

“even be defended on the ground that it rationally sets

apart a group of persons who are particularly likely to

commit perjury” since the rule allowed an alleged participant to testify if he or she had been acquitted or was 

called by the prosecution. Id., at 22–23. 

A similar constitutional violation occurred in Chambers 

v. Mississippi, supra. A murder defendant called as a 

witness a man named McDonald, who had previously 

confessed to the murder. When McDonald repudiated the

confession on the stand, the defendant was denied permission to examine McDonald as an adverse witness based on 

the State’s “‘voucher’ rule,” which barred parties from

impeaching their own witnesses. Id., at 294. In addition, 

because the state hearsay rule did not include an exception for statements against penal interest, the defendant

was not permitted to introduce evidence that McDonald

had made self-incriminating statements to three other 

persons. Noting that the State had not even attempted to

“defend” or “explain [the] underlying rationale” of the 

“voucher rule,” id., at 297, this Court held that “the exclusion of [the evidence of McDonald’s out-of-court statements], coupled with the State’s refusal to permit [the

defendant] to cross-examine McDonald, denied him a trial

in accord with traditional and fundamental standards of 

due process,” id., at 302. 

Another arbitrary rule was held unconstitutional in 

Crane v. Kentucky, supra. There, the defendant was pre-
6 HOLMES v. SOUTH CAROLINA 

Opinion of the Court 

vented from attempting to show at trial that his confession 

was unreliable because of the circumstances under which 

it was obtained, and neither the State Supreme Court nor

the prosecution “advanced any rational justification for

the wholesale exclusion of this body of potentially exculpatory evidence.” Id., at 691. 

In Rock v. Arkansas, supra, this Court held that a rule 

prohibiting hypnotically refreshed testimony was unconstitutional because “[w]holesale inadmissibility of a defendant’s testimony is an arbitrary restriction on the right to

testify in the absence of clear evidence by the State repudiating the validity of all post-hypnotic recollections.” Id., 

at 61. By contrast, in United States v. Scheffer, supra, we 

held that a rule excluding all polygraph evidence did not 

abridge the right to present a defense because the rule

“serve[d] several legitimate interests in the criminal trial

process,” was “neither arbitrary nor disproportionate in 

promoting these ends,” and did not “implicate a sufficiently weighty interest of the defendant.” Id., at 309. 

While the Constitution thus prohibits the exclusion of

defense evidence under rules that serve no legitimate

purpose or that are disproportionate to the ends that they

are asserted to promote, well-established rules of evidence

permit trial judges to exclude evidence if its probative 

value is outweighed by certain other factors such as unfair 

prejudice, confusion of the issues, or potential to mislead 

the jury. See, e.g., Fed. Rule Evid. 403; Uniform Rule of 

Evid. 45 (1953); ALI, Model Code of Evidence Rule 303

(1942); 3 J. Wigmore, Evidence §§1863, 1904 (1904). 

Plainly referring to rules of this type, we have stated that

the Constitution permits judges “to exclude evidence that

is ‘repetitive . . . , only marginally relevant’ or poses an

undue risk of ‘harassment, prejudice, [or] confusion of the 

issues.’” Crane, supra, at 689–690 (quoting Delaware v. 

Van Arsdall, 475 U. S. 673, 679 (1986); ellipsis and brackets in original). See also Montana v. Egelhoff, 518 U. S. 37, 
Cite as: 547 U. S. ____ (2006) 7 

Opinion of the Court 

42 (1996) (plurality opinion) (terming such rules “familiar 

and unquestionably constitutional”).

A specific application of this principle is found in rules

regulating the admission of evidence proffered by criminal 

defendants to show that someone else committed the 

crime with which they are charged. See, e.g., 41 C. J. S., 

Homicide §216, pp. 56–58 (1991) (“Evidence tending to 

show the commission by another person of the crime

charged may be introduced by accused when it is inconsistent with, and raises a reasonable doubt of, his own guilt; 

but frequently matters offered in evidence for this purpose 

are so remote and lack such connection with the crime 

that they are excluded”); 40A Am. Jur. 2d, Homicide §286, 

pp. 136–138 (1999) (“[T]he accused may introduce any 

legal evidence tending to prove that another person may

have committed the crime with which the defendant is 

charged . . . . [Such evidence] may be excluded where it 

does not sufficiently connect the other person to the crime, 

as, for example, where the evidence is speculative or remote, or does not tend to prove or disprove a material fact

in issue at the defendant’s trial” (footnotes omitted)).

Such rules are widely accepted,* and neither petitioner 

—————— 

* See, e.g., Smithart v. State, 988 P. 2d 583, 586–587 (Alaska 1999); 

Shields v. State, 357 Ark. 283, 287–288, 166 S. W. 3d 28, 32 (2004); 

People v. Hall, 41 Cal. 3d 826, 833, 718 P. 2d 99, 103–104 (1986) (en 

banc); People v. Mulligan, 193 Colo. 509, 517–518, 568 P. 2d 449, 456– 

457 (1977) (en banc); State v. West, 274 Conn. 605, 624–627, 877 A. 2d 

787, 802–803 (2005); Winfield v. United States, 676 A. 2d 1 (DC App. 

1996) (en banc); Klinect v. State, 269 Ga. 570, 573, 501 S. E. 2d 810, 

813–814 (1998); State v. Rabellizsa, 79 Haw. 347, 350–351, 903 P. 2d 

43, 46–47 (1995); People v. Fort, 248 Ill. App. 3d 301, 314, 618 N. E. 2d 

445, 455 (1993); State v. Adams, 280 Kan. 494, 504–507, 124 P. 3d 19, 

27–29 (2005); Beaty v. Commonwealth, 125 S. W. 3d 196, 207–208 (Ky. 

2003); State v. Dechaine, 572 A. 2d 130, 134 (Me. 1990); Commonwealth 

v. Scott, 408 Mass. 811, 815–816, 564 N. E. 2d 370, 374–375 (1990); 

State v. Jones, 678 N. W. 2d 1, 16–17 (Minn. 2004); Moore v. State, 179 

Miss. 268, 274–275, 175 So. 183, 184 (1937); State v. Chaney, 967 S. W. 

2d 47, 55 (Mo. 1998) (en banc); State v. Cotto, 182 N. J. 316, 332–333, 
8 HOLMES v. SOUTH CAROLINA 

Opinion of the Court 

nor his amici challenge them here.

In Gregory, the South Carolina Supreme Court adopted 

and applied a rule apparently intended to be of this type,

given the court’s references to the “applicable rule” from

Corpus Juris and American Jurisprudence: 

“‘[E]vidence offered by accused as to the commission 

of the crime by another person must be limited to such

facts as are inconsistent with his own guilt, and to

such facts as raise a reasonable inference or presumption as to his own innocence; evidence which can have 

(no) other effect than to cast a bare suspicion upon

another, or to raise a conjectural inference as to the

commission of the crime by another, is not admissible. . . . [B]efore such testimony can be received, there

must be such proof of connection with it, such a train

of facts or circumstances, as tends clearly to point out

such other person as the guilty party.’” 198 S. C., at 

104–105, 16 S. E. 2d, at 534–535 (quoting 16 C. J., 

Criminal Law §1085, p. 560 (1918) and 20 Am. Jur.,

Evidence §265, p. 254 (1939); footnotes omitted). 

In Gay and this case, however, the South Carolina 

Supreme Court radically changed and extended the rule. 

In Gay, after recognizing the standard applied in Gregory, 

the court stated that “[i]n view of the strong evidence of 

appellant’s guilt—especially the forensic evidence—. . . the 

proffered evidence . . . did not raise ‘a reasonable inference’ as to appellant’s own innocence.” Gay, 343 S. C., at 

—————— 

865 A. 2d 660, 669–670 (2005); Gore v. State, 2005 OK CR 14, ¶¶13–24, 

119 P. 3d 1268, 1272–1276; State v. Gregory, 198 S. C. 98, 104–105, 16

S. E. 2d 532, 534–535 (1941); Wiley v. State, 74 S. W. 3d 399, 405–408 

(Tex. Crim. App. 2002); State v. Grega, 168 Vt. 363, 375, 721 A. 2d 445, 

454 (1998); State v. Thomas, 150 Wash. 2d 821, 856–858, 83 P. 3d 970, 

988 (2004) (en banc); State v. Parr, 207 W. Va. 469, 475, 534 S. E. 2d 

23, 29 (2000) (per curiam); State v. Denny, 120 Wis. 2d 614, 622–625, 

357 N. W. 2d 12, 16–17 (Wis. App. 1984). 
Cite as: 547 U. S. ____ (2006) 9 

Opinion of the Court 

550, 541 S. E. 2d, at 545 (quoting Gregory, supra, at 104, 

16 S. E. 2d, at 534, in turn quoting 16 C. J., §1085, at 560). 

Similarly, in the present case, as noted, the State Supreme 

Court applied the rule that “where there is strong evidence of [a defendant’s] guilt, especially where there is 

strong forensic evidence, the proffered evidence about a 

third party’s alleged guilt” may (or perhaps must) be

excluded. 361 S. C., at 342, 605 S. E. 2d, at 24. 

Under this rule, the trial judge does not focus on the

probative value or the potential adverse effects of admitting the defense evidence of third-party guilt. Instead, the 

critical inquiry concerns the strength of the prosecution’s

case: If the prosecution’s case is strong enough, the evidence of third-party guilt is excluded even if that evidence, 

if viewed independently, would have great probative value

and even if it would not pose an undue risk of harassment, 

prejudice, or confusion of the issues. 

Furthermore, as applied in this case, the South Carolina

Supreme Court’s rule seems to call for little, if any, examination of the credibility of the prosecution’s witnesses or 

the reliability of its evidence. Here, for example, the defense strenuously claimed that the prosecution’s forensic 

evidence was so unreliable (due to mishandling and a 

deliberate plot to frame petitioner) that the evidence

should not have even been admitted. The South Carolina 

Supreme Court responded that these challenges did not

entirely “eviscerate” the forensic evidence and that the 

defense challenges went to the weight and not to the admissibility of that evidence. Id., at 343, n. 8, 605 S. E. 2d, 

at 24, n. 8. Yet, in evaluating the prosecution’s forensic 

evidence and deeming it to be “strong”—and thereby justifying exclusion of petitioner’s third-party guilt evidence—

the South Carolina Supreme Court made no mention of the

defense challenges to the prosecution’s evidence. 

Interpreted in this way, the rule applied by the State 

Supreme Court does not rationally serve the end that the 
10 HOLMES v. SOUTH CAROLINA 

Opinion of the Court 

Gregory rule and its analogues in other jurisdictions were

designed to promote, i.e., to focus the trial on the central 

issues by excluding evidence that has only a very weak

logical connection to the central issues. The rule applied 

in this case appears to be based on the following logic:

Where (1) it is clear that only one person was involved in

the commission of a particular crime and (2) there is

strong evidence that the defendant was the perpetrator, it 

follows that evidence of third-party guilt must be weak. 

But this logic depends on an accurate evaluation of the 

prosecution’s proof, and the true strength of the prosecution’s proof cannot be assessed without considering challenges to the reliability of the prosecution’s evidence. Just 

because the prosecution’s evidence, if credited, would 

provide strong support for a guilty verdict, it does not

follow that evidence of third-party guilt has only a weak

logical connection to the central issues in the case. And 

where the credibility of the prosecution’s witnesses or the 

reliability of its evidence is not conceded, the strength of 

the prosecution’s case cannot be assessed without making 

the sort of factual findings that have traditionally been

reserved for the trier of fact and that the South Carolina 

courts did not purport to make in this case. 

The rule applied in this case is no more logical than its

converse would be, i.e., a rule barring the prosecution from 

introducing evidence of a defendant’s guilt if the defendant

is able to proffer, at a pretrial hearing, evidence that, if 

believed, strongly supports a verdict of not guilty. In the 

present case, for example, the petitioner proffered evidence that, if believed, squarely proved that White, not 

petitioner, was the perpetrator. It would make no sense, 

however, to hold that this proffer precluded the prosecution from introducing its evidence, including the forensic

evidence that, if credited, provided strong proof of the 

petitioner’s guilt.

The point is that, by evaluating the strength of only one 
Cite as: 547 U. S. ____ (2006) 11 

Opinion of the Court 

party’s evidence, no logical conclusion can be reached 

regarding the strength of contrary evidence offered by the 

other side to rebut or cast doubt. Because the rule applied 

by the State Supreme Court in this case did not heed this 

point, the rule is “arbitrary” in the sense that it does not

rationally serve the end that the Gregory rule and other 

similar third-party guilt rules were designed to further. 

Nor has the State identified any other legitimate end that

the rule serves. It follows that the rule applied in this case

by the State Supreme Court violates a criminal defendant’s 

right to have “‘a meaningful opportunity to present a complete defense.’” Crane, 476 U. S., at 690 (quoting Trombetta, 467 U. S., at 485). 

III 

For these reasons, we vacate the judgment of the South

Carolina Supreme Court and remand the case for further

proceedings not inconsistent with this opinion. 

It is so ordered.