On June 13, 2013 the United States Supreme Court issued its decision in Tarrant Regional Water District v. Herrmann et al., regarding the rights of Texas to access water in Oklahoma under the Red River Compact. The case began when the Tarrant Regional Water District (“Tarrant”) located in Texas, brought suit to effectively compel Oklahoma to allow it to divert river flows in Oklahoma, to serve the growing population of north Texas. Tarrant argued that the Red River Compact expressly granted to Texas the right to certain flows in Oklahoma and that Oklahoma’s state law prohibiting the exportation of water was a violation of the federal Constitution’s Commerce Clause. Oklahoma argued that although Texas had a right to use a portion of the flows, it did not have the right to access such water in Oklahoma and in a manner that was contrary to Oklahoma state law. The Court found the Compact’s silence on the issue of cross-border access evidenced the intent of the compacting states to retail their raditional authorities over water. The Court reasoned that because the Compact did not expressly authorize one state to access water in another state, the parties must have intended to retain the authority to control access to the water pursuant to their own state laws. Texas, therefore, did not have the right to divert the water in Oklahoma unless it first complied with Oklahoma state law. The Court further concluded that because the Compact fully allocated the river, Oklahoma state law could have no impact on interstate commerce and therefore could not run afoul of the Commerce Clause. The Court’s decision affirmed the ruling of the Tenth Circuit Court of Appeals.