In the case of Ivan V. v. City of New York (1971), the U.S Supreme Court addressed issues related to child welfare and parental rights. The plaintiff, a minor named Ivan, was removed from his mother's care by New York City officials due to allegations of neglect. His mother had been hospitalized for psychiatric treatment at that time and was unable to provide proper care for him. However, she wasn't given an opportunity for a hearing before or after her son’s removal which led her to file a lawsuit against the city claiming violation of their constitutional rights under Fourteenth Amendment's Due Process Clause. The court ruled in favor of Ivan and his mother stating that parents have constitutionally protected liberty interest in maintaining custody over their children unless they are proven unfit through due process procedures such as fair hearings where evidence is presented and evaluated impartially. This landmark decision set precedence on how state agencies should handle cases involving potential child abuse or neglect ensuring protection not only for children but also safeguarding parental rights under law.

In the dissenting opinion for Ivan V. City of New York, 1971, it was argued that the majority's decision to uphold a law prohibiting loitering without considering its potential for arbitrary enforcement and abuse was misguided. The dissent emphasized that such laws could be used by authorities as tools of harassment against individuals or groups they disfavor, thus infringing upon their constitutional rights. Furthermore, it was pointed out that vague statutes like this one leave citizens uncertain about what behavior is actually prohibited and give police excessive discretion in deciding whom to arrest. This lack of clarity can lead to inconsistent application and interpretation of the law which undermines its legitimacy and fairness. Therefore, according to the dissenters' view, this anti-loitering statute should have been struck down as unconstitutional due to its vagueness and potential for discriminatory enforcement.