In the United States v. Sandoval case of 1896, the U.S Supreme Court ruled that Congress had authority over Native American tribes and their lands through its plenary power. The case involved a man named Sandoval who was charged with introducing alcohol into Pueblo Indian territory in New Mexico, which violated federal law at that time. He argued that this law did not apply to him because he believed the Pueblos were not recognized as an Indian tribe under federal jurisdiction and thus could not be subject to these laws. However, the court disagreed with his argument stating that it is up to Congress - rather than courts or states - to determine whether certain groups are considered 'tribes' under federal law. Therefore, they concluded that since Congress had previously passed legislation recognizing Pueblos as a tribe and protecting their land rights, they indeed fell under congressional authority making them subject to relevant laws including those prohibiting alcohol on tribal lands.

The United States v. Sandoval case in 1896 does not have a recorded dissenting opinion available for summarization. It's possible that there may be some confusion regarding the date or details of this case, as the most notable Supreme Court Case involving a defendant named Sandoval took place in 1913 (United States v. Sandoval), and it was decided unanimously without any noted dissents. Please provide additional information to ensure an accurate summary is provided.