In the 1904 case of Ah Sin v. Wittman, a Chinese immigrant named Ah Sin was arrested in California for playing a game called Tan, which he argued was not gambling but rather a game of skill. The Supreme Court had to determine whether this arrest violated the Fourteenth Amendment's Equal Protection Clause because white people were often allowed to play similar games without being arrested or charged. However, the court ruled against Ah Sin and upheld his conviction on two grounds: firstly that there was no evidence presented showing discriminatory enforcement of laws against him due to his race; secondly that even if such discrimination existed it would be an issue with law enforcement officers' conduct and not with the law itself. This decision effectively sanctioned racial bias in law enforcement by allowing authorities to selectively enforce laws based on race as long as those laws did not explicitly discriminate.

In the dissenting opinion for AH SIN v. WITTMAN, Justice Harlan argued that Ah Sin was unjustly targeted and arrested simply because he was Chinese and suspected of being a gambler. He believed that this case represented an abuse of power by local law enforcement who used discriminatory laws to harass Chinese immigrants without just cause. According to him, the ordinance under which Ah Sin was arrested violated his Fourteenth Amendment rights as it only applied to games predominantly played by people of Chinese descent while ignoring similar activities among other racial groups. Therefore, in his view, such selective enforcement constituted unequal protection under the law based on race or nationality which is unconstitutional according to the Equal Protection Clause of the Fourteenth Amendment.