Throughout her main argument, Petitioner's attorney stuck with the point that the Confrontation Clause as understood by the Framers, as well as the common law, prohibited a testimonial statement from being admitted as evidence unless other evidence showed the defendant intended to tamper with the witness and prevent his testimony at trial. Justice Scalia often chimed in to help her with this argument, reminding the Court that Crawford v. Washington had already defined the contours of the Confrontation Clause. Post-Crawford, testimonial statements are inadmissible at trial unless the defendant has had an opportunity to cross-examine the witness.

While Justice Breyer attempted to draw Petitioner into a discussion as to whether strict adherence to the common law made sense in all cases, Justice Scalia and Petitioner reminded the Court that the exception to the Confrontation Clause advocated by California was not recognized under Crawford.

In response, the Respondent, California, argued for a rule that the common law did not recognize a confrontation right for a person who had murdered the witness against him. This rule is broader than the current Federal Rule of Evidence 804(b)(6) which requires proof of an intent to silence or tamper with a witness before a testimonial statement may be admitted against the defendant. Both Chief Justice Roberts and Justice Kennedy expressed concern over this rule with the Chief Justice expressing concern that if such a rule were allowed it would not be limited to those cases where it is most necessary, for example, domestic violence cases.

Respondent failed to satisfy these concerns by articulating a rule that could both satisfy the Justices' desire to preserve the right to confrontation, but allow testimonial statements made by the victim regarding the manner in which he or she was killed. Respondent's best argument for adopting California's rule was that dying declarations were allowed under the common law as a hearsay exception, and the Court should view this as "insight into how the common law would have devalued the confrontation rights of the killer."

While she initially seemed to side with California, Justice Ginsburg's closing comments appeared to favor the Petitioner. During Petitioner's rebuttal Justice Ginsburg asked if all that Petitioner wanted was harmless-error analysis. Petitioner's response that yes, all Petitioner wanted was a fair trial with a rule that was not "concocted for the broad purpose of eviscerating Crawford" may have sealed the deal.

If the Court does decide for Petitioner it will be interesting to see how states that have adopted rules like the one advocated by California will respond. Post-Crawford, there remain strong policy arguments for allowing a testimonial statement made by a battered wife or abused child to be admitted at trial when the defendant has killed the witness, even though he or she may not have killed to silence the witness at trial. While Giles may not be the case that decides this rule, hopefully one will come along that does.