Who strengthened the power of the federal government?

The power of the federal government was significantly strengthened by various leaders and events throughout U.S. history, notably during the presidency of Franklin D. Roosevelt. His New Deal programs expanded federal authority over the economy and introduced a range of social welfare initiatives. Additionally, the Supreme Court's rulings have often upheld federal power, particularly during the 20th century, reinforcing the government's role in regulating commerce and civil rights. The Civil War and the subsequent Reconstruction era also played crucial roles in affirming federal supremacy over states' rights.