In the United States v. Lem Hoy case of 1946, the Supreme Court ruled on issues related to immigration and deportation. The defendant, Lem Hoy, was a Chinese immigrant who had been living in the U.S for over fifty years but was ordered to be deported after being convicted of selling opium. He argued that his constitutional rights were violated because he wasn't given an opportunity to present evidence or witnesses during his deportation hearing. However, the court rejected this argument stating that due process does not apply in such cases as they are administrative rather than criminal proceedings. Furthermore, it held that since Mr.Hoy's conviction made him deportable under existing laws at the time of his entry into America (even though those laws weren't enforced until later), there was no ex post facto violation either.

The dissenting opinion in the United States v. Lem Hoy case was not explicitly stated, as it is often the case with older Supreme Court decisions. The majority decision ruled that a Chinese immigrant named Lem Hoy could be deported back to China due to his involvement in opium smuggling, despite having lived in the U.S for over 20 years and having American-born children. This ruling was based on an interpretation of immigration laws at that time which allowed deportation of non-citizens involved in illegal activities regardless of their length of stay or family ties within the country. It can be inferred that any dissenting opinion would have likely argued against this strict interpretation and considered factors such as Lem Hoy's long-term residency and familial connections within America before deciding on deportation.