The U.S. Supreme Court case Connecticut Light & Power Co. v. Federal Power Commission in 1944 revolved around the jurisdiction of the Federal Power Commission (FPC) over a hydroelectric project constructed by the Connecticut Light and Power Company on non-navigable waters, but which affected navigable waters downstream due to its connection with them through other streams and rivers. The FPC had issued an order requiring the company to obtain a license for this project under Section 23(b) of the Federal Water Power Act, arguing that it was within their authority as it impacted interstate commerce via its effect on navigable waters downstream. Connecticut Light & Power challenged this decision, asserting that since they were operating solely within state boundaries on non-navigable waterways, federal regulation should not apply. However, upon reaching the Supreme Court, justices ruled in favor of FPC's assertion that any construction affecting navigational capacity or potential energy production from water resources connected to interstate commerce fell under federal jurisdiction regardless of where exactly those constructions took place. This ruling affirmed FPC’s regulatory power over such projects even if they are located entirely within one state's borders when there is an impact on interstate commerce.

The dissenting opinion in the case of Connecticut Light & Power Co. v. Federal Power Commission argued that the majority's decision to uphold the Federal Power Commission's authority over wholesale electricity rates was an overreach of federal power, infringing on states' rights to regulate their own utilities. The dissenters believed that Congress did not intend for such a broad interpretation of its powers when it passed the Federal Water Power Act and other related legislation, which they saw as focused more on promoting fair competition than on direct rate regulation. They also expressed concerns about potential negative impacts on private utility companies and state regulatory bodies due to this expanded federal control.