In the 1906 case United States v. Riggs, the U.S Supreme Court dealt with a dispute over land ownership in Oklahoma. The plaintiff, William M. Riggs, claimed that he had purchased a tract of land from an individual who held it under an allotment deed issued by the Secretary of Interior on behalf of a member of Choctaw and Chickasaw tribes. However, this sale was made without approval from the Secretary which was required by law for such transactions involving Native American lands allotted to tribal members. The government argued that since there was no official approval for this transaction as mandated by law, Mr.Riggs did not have valid title to the property and hence sought its recovery through legal proceedings. The court ruled in favor of United States stating that any conveyance or contract affecting lands allotted to tribal members must be approved by Secretary before they can take effect legally; otherwise they are considered null and void ab initio (from inception). Therefore Mr.Riggs' claim over property based on unapproved purchase was invalid making him ineligible for holding title over said piece of land.

The dissenting opinion in the United States v. Riggs case of 1906 is not available or does not exist. The details about this specific case are scarce and it's unclear whether there was a dissenting opinion at all. It appears that this particular court decision may have been unanimous, or if there was any disagreement among the justices, it wasn't significant enough to warrant a written dissenting opinion.