In a 6-3 decision, the Court held that Trump's deployment of the National Guard exceeded the authority granted to him by federal law. The Court's majority opinion, written by Justice Sonia Sotomayor, found that the president's actions were "unlawful and unconstitutional." The decision was joined by three Republican justices, including Chief Justice John Roberts, who has often been seen as a swing vote on the Court.

"We cannot allow the president to use the military to silence dissent and suppress free speech," Sotomayor wrote in her opinion. "The Constitution guarantees the right to peaceful protest, and we will not stand idly by while the president seeks to undermine that right."

The decision was welcomed by civil liberties groups, who argued that Trump's deployment of the National Guard was a clear overreach of executive authority. "This decision is a major victory for the rule of law and the Constitution," said ACLU Executive Director Anthony Romero. "We are thrilled that the Court has recognized the importance of protecting the right to peaceful protest."

Trump's lawyers had argued that the president had the authority to deploy the National Guard to maintain order and protect the safety of protesters. However, the Court's majority disagreed, finding that the president's actions were not justified by the circumstances.

The decision marks a significant shift in the Court's approach to executive authority, which has been a major issue in recent years. In 2020, the Court ruled in a 5-4 decision that Trump had the authority to use military force against protesters in Portland, Oregon. However, the Court's decision in Trump v. Illinois suggests that the Court is now taking a more nuanced approach to executive authority.

The decision has significant implications for the future of executive power and the role of the military in domestic law enforcement. As the Court's decision makes clear, the president's authority to deploy the military is not unlimited, and the Court will continue to play a crucial role in ensuring that the executive branch does not overstep its bounds.

The case is now closed, but the implications of the decision will be felt for years to come. The Court's decision is a reminder that the Constitution is a living document, and that the Court will continue to play a vital role in ensuring that the rights and liberties of all Americans are protected.