Hagar v. Reclamation District No. 108 was a United States Supreme Court case that addressed the issue of whether a state court could enjoin a federal officer from performing his duties. The case involved a dispute between the Reclamation District No. 108 and the United States government over the construction of a levee along the Sacramento River. The district sought to enjoin the United States from constructing the levee, claiming that it would interfere with their rights to the river. The United States argued that the district had no authority to enjoin a federal officer from performing his duties. The Supreme Court held that the district had no authority to enjoin a federal officer from performing his duties. The Court reasoned that the district was a state entity and, as such, was not authorized to interfere with the federal government's authority. The Court further held that the district's attempt to enjoin the federal officer was an unconstitutional interference with the federal government's authority. The Court concluded that the district had no authority to enjoin the federal officer from performing his duties. In conclusion, the Supreme Court held that the district had no authority to enjoin a federal officer from performing his duties. The Court reasoned that the district was a state entity and, as such, was not authorized to interfere with the federal government's authority. The Court further held that the district's attempt to enjoin the federal officer was an unconstitutional interference with the federal government's authority.

Justice Harlan wrote a dissenting opinion in the case of Hagar v. Reclamation District No. 108, arguing that Congress had not intended to limit its power over navigable waters when it passed the Reclamation Act of 1902. He argued that this was evident from both the language and legislative history of the act, which showed an intent to give broad powers to states for reclaiming land by means other than navigation or commerce on navigable waters. Furthermore, he noted that if Congress had meant to limit its power over such matters, it would have done so explicitly in either the text or legislative history of the act itself. In conclusion, Justice Harlan believed that Congress did not intend for state reclamation projects like those at issue here to be subject solely to federal control under admiralty law; rather they should also be subject to state regulation as well as congressional oversight through legislation specifically addressing them.