The Supreme Court issued a trio of decisions over the past week that put new checks on federal agencies’ regulatory powers. The rulings cap off a momentous term for the court that stands to reshape financial regulation in the coming years.

The three decisions issued Monday and on Thursday and Friday last week dealt a body blow to the administrative state, and may spur a wave of new litigation. And while they may reduce regulatory oversight over the wealth management industry in coming years, they are likely to increase compliance…