Two cases decided in the 2005-06 term help illustrate the rationale for classifying outcomes as conservative or liberal, as well as the peril of trying to classify justices as being conservative or liberal. The companion cases of Davis v. Washington (2005) and Hammon v. Indiana (2005) permitted the Court to distinguish testimonial and nontestimonial statements to the police. The Sixth Amendment guarantees an individual accused of a crime the right " to be confronted with the witnesses against him." Judgments that support and expand this right may be perceived as more liberal while judgments that attempt to constrain and limit this right would be deemed as more conservative.
Previously, in Ohio v. Roberts (1980), a divided Court permitted testimony given by a witness at a preliminary hearing to be used at a trial when the witness failed to appear at the trial. The absence of the witness did not therefore permit any cross-examination by the defense, which subsequently on appeal asserted a violation of the Sixth Amendment right to be confronted by witnesses against one. A liberal stance would support this claim of individual liberty and protection while a conservative position would tolerate this lack of opportunity, assuming the preliminary hearing provided sufficient reliability regarding the truthfulness of the testimony. The U.S. permitted the preliminary hearing testimony to be used at trial by a 6 to 3 vote. In dissent were the three justices commonly recognized as the most liberal on the Court at that time—Brennan, Marshall, and Stevens. In a subsequent case, Crawford v. Washington (2004), Roberts was effectively overruled. Justice Scalia penned the opinion in the unanimous judgment preventing a recorded statement made to police during interrogation from being used in the trial. In so doing, Scalia appears to author a liberal outcome. In this instance, however, the liberal position is fundamentally libertarian in nature. Siding with a liberal or a conservative position does not make one a liberal or a conservative.
Now come the Davis v. Washington and Hammon v. Indiana cases. To expand what encompasses testimonial statements extends individual rights and would be considered a more liberal position. To expand the definition of nontestimonial and restrict testimonial statements would constitute a more conservative position. By unanimously classifying a 9-1-1 call as a nontestimonial statement not subject to the confrontation right of the Sixth Amendment, the Court adopted a conservative stance. Then distinguishing the Hammon case by declaring the police interrogation in the home as testimonial in nature, and not admissible per se in trial unless the witness appeared, the Court favored the liberal position with all but one of the justices concurring. Again, Scalia authored the sole opinion for these two cases, but perhaps it is no accident that the lone dissenter was Thomas, identified in the 2005-06 data as the justice most often in line with conservative positions, who concurred regarding Davis but dissented regarding Hammon.
These cases illustrate that the justices do perceive Constitutional constraints and that there are perils in imposing labels on the justices with respect to the judgments that they make. With that in mind, it is still useful to note that voting commonalities among the justices are present and can serve to assess voting behavior and predict likely outcomes with respect to issues that lend themselves to ideological denotation.