In the case of Lane v. Wilson, 1938, the U.S. Supreme Court ruled that an Oklahoma law was unconstitutional because it violated the Fifteenth Amendment by discriminating against African-American voters. The law in question had been enacted to replace a previous "grandfather clause" which had also been deemed unconstitutional for its discriminatory nature towards black citizens. This new legislation required all individuals who were not registered to vote prior to 1916 and did not register during a twelve-day period in April 1916, would be perpetually disenfranchised unless they could meet stringent literacy and property requirements - conditions disproportionately difficult for African-Americans at that time due to systemic racism and economic inequality. The court held that this law was just as racially biased as its predecessor since it continued to unfairly target African Americans' right to vote.

In the dissenting opinion for Lane v. Wilson, Justice McReynolds disagreed with the majority's decision to invalidate Oklahoma's 1916 voting registration law on grounds of racial discrimination. He argued that there was insufficient evidence to prove that the law had been designed or operated in a way that systematically excluded black citizens from registering to vote. Furthermore, he contended that it was not within the Supreme Court’s jurisdiction to question whether state laws were wise or unwise; their only duty was determining if they violated constitutional rights. In his view, since no clear violation could be proven in this case, it should have been dismissed outright rather than being remanded back down for further proceedings as per the majority ruling.