The Delaware Supreme Court’s landmark ruling Friday completed a trilogy of high-profile decisions that signal the justices want to shore up the state’s business-friendly reputation, quiet the “DExit” noise, and get out from under the political attacks—particularly those fueled by Elon Musk.

The unanimous opinion upholding a controversial legislative overhaul comes after the court restored Musk’s $56 billion pay package with Tesla Inc. and revived Ken Moelis’ contractual control over his namesake investment bank. The latter two rulings overturned decisions that had business leaders threatening to flee America’s corporate capital while looking to lawmakers and the high court for …