Shaw oversaw numerous cases related to slave law and race. In 1836, Shaw's opinion in Commonwealth v. Aves held that a slave brought voluntarily into Massachusetts, a free state, was a "sojourner," or a journeyer, and not taking domicile in that state. Therefore, slaves could be brought into the state only for a limited time. Abolitionists, who had brought the habeas corpus suit, wanted a rule which would have freed the girl, while southern defenders of the practice wanted the court to uphold the concept of comity and acknowledge the legality of slavery. Shaw attempted to split the decision by applying the archaic "sojourner" status to slaves. Further, Shaw rejected the doctrine of interstate comity. In his strict understanding, comity is a vehicle for facilitating trade and amicable interactions between jurisdictions. Therefore, Shaw reasoned that a state or jurisdiction is not required to honor comity if in doing so it is sanctioning practices repugnant to the state's own norms. The Aves case caused an uproar in the South where planters accused the Northerners of denying their equal sovereign status. Shaw also drew criticism from conservative jurists in other Northern states, as in State v. Post (N.J. 1845). His ruling in favor of the constitutionality of school segregation in Roberts v. City of Boston (1849) established "separate but equal" as a legal doctrine in the state. In a later case, he again refused to release fugitive slave Thomas Sims on habeas corpus grounds, as he felt bound by the Constitution and the law, as the recent Fugitive Slave Act of 1850 required states and local governments to cooperate in the capture of escaped slaves. Sims' Case was the first by any court in the United States to uphold the constitutionality of the Fugitive Slave Act. Commonwealth v. Webster (1850) No single case brought Shaw such criticism or such respect as the Parkman–Webster murder case, i.e. Commonwealth v. Webster, held in Boston in March 1850. While Shaw was Chief Justice, the Supreme Judicial Court still possessed exclusive jurisdiction over all capital crimes: capital cases were tried by a jury presided over by the Chief Justice attended by his associate justices. At such a trial all points of law were argued fully by counsel and settled on the spot by decisions as 'final and conclusive' as those of the highest appellate court on a bill of exceptions. Such an accommodation was rooted in