Tucker & Another v. Masser & Others was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of mandamus to compel a county court to issue a deed to a party. The Supreme Court held that the state court did not have the authority to issue such a writ. The case arose when the plaintiffs, Tucker and another, sought to compel the county court of Pennsylvania to issue a deed to them for a tract of land. The county court refused to issue the deed, and the plaintiffs then sought a writ of mandamus from the state court to compel the county court to issue the deed. The state court granted the writ, and the county court appealed to the Supreme Court. The Supreme Court held that the state court did not have the authority to issue the writ of mandamus. The Court reasoned that the writ of mandamus was a judicial remedy, and that the state court did not have the authority to issue such a writ to a county court. The Court further held that the writ of mandamus was not a proper remedy for the plaintiffs, as the county court had the authority to issue the deed without the writ. In conclusion, the Supreme Court held that the state court did not have the authority to issue a writ of mandamus to compel the county court to issue a deed to the plaintiffs. The Court held that the writ of mandamus was not a proper remedy for the plaintiffs, as the county court had the authority to issue the deed without the writ.

In Tucker & Another v. Masser & Others, the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by citizens of one state against citizens of another in which the amount in controversy exceeded $500. The majority opinion held that it did not have such jurisdiction because the Constitution does not grant states authority to exercise judicial power over controversies between citizens of different states unless Congress has authorized them to do so. Justice Field dissented from this decision and argued that under Article III, Section 2, Clause 1 of the Constitution, a state court may take cognizance of any suit where there is diversity between parties if its value exceeds $500; thus he believed that Congress could not limit or restrict this right granted by the Constitution without violating it. He further argued that since no act had been passed denying or restricting this right for suits involving more than $500, then these cases should be heard in state courts as they are within their constitutional powers and rights.