In the case of CTS Corp. v. Dynamics Corporation of America, 1986, the U.S Supreme Court ruled in favor of CTS Corp., upholding an Indiana law that required any entity seeking to acquire more than 20% of a corporation's stock to receive approval from existing shareholders before proceeding with the acquisition. The court held that this law did not violate the Commerce Clause or Supremacy Clause as argued by Dynamics Corporation because it was within a state’s power to regulate corporations and protect local interests without unduly burdening interstate commerce. This ruling affirmed states' rights to enact laws protecting their corporate citizens against hostile takeovers.

In the dissenting opinion for CTS Corp. v. Dynamics Corporation of America, Justice Blackmun argued that Indiana's Control Shares Acquisition Act was unconstitutional as it violated the Commerce Clause by discriminating against interstate commerce. He believed that this law unfairly burdened out-of-state corporations seeking to acquire shares in Indiana companies and thus interfered with a national market for corporate control. Furthermore, he disagreed with the majority’s view that states have an interest in promoting shareholder participation or preventing corporate raiders from reaping short-term profits at long-term costs to target companies and their communities; instead, he asserted these were matters of federal concern under securities laws rather than state corporation laws. Finally, Justice Blackmun criticized the majority’s reliance on evidence not presented at trial about supposed benefits of such statutes without any empirical support.