In the Northern Pacific Railroad Company v. O'Brien case of 1894, the U.S Supreme Court ruled in favor of Northern Pacific Railroad Company. The dispute arose when O'Brien claimed that he had a right to a piece of land under an act passed by Congress in 1870 granting lands to several states for railroad construction purposes. However, this particular parcel was part of the land granted by Congress to the Northern Pacific Railroad Company in 1864 for building their rail line before it was given to any state under the Act of 1870. The court held that since these lands were already vested with another entity (the railroad company) prior to passing on such rights through subsequent legislation, they could not be claimed by anyone else including Mr.O’Brien who based his claim on later laws or grants from government bodies like states which received them after initial allocation.

In the dissenting opinion for Northern Pacific Railroad Company v. O'Brien, Justice Brewer argued that the majority's decision was inconsistent with previous rulings and failed to consider important factors. He contended that the railroad company had a valid claim to land under an 1864 Act of Congress granting it certain lands in Minnesota and Montana, which included those at issue in this case. The majority held that because these lands were not adjacent to its main line of road but instead lay along branches built after 1870, they did not fall within the grant. However, Justice Brewer disagreed with this interpretation of "main line," arguing it should include all lines constructed as part of one continuous work undertaken by a single corporation under one general power from Congress. Furthermore, he pointed out that even if some parts were completed later than others due to practical reasons or financial constraints shouldn't affect their inclusion in the grant since there was no time limit specified by Congress for completion.