On June 17, 2021, the U.S. Supreme Court in California v. Texas rejected a challenge to the Affordable Care Act (the "ACA") by holding the plaintiffs lacked standing to bring suit. In 2018, Texas, along with a coalition of over a dozen states and two individuals, brought suit challenging the constitutionality of the individual mandate under the ACA after the penalty for failing to comply was set to zero dollars in 2017. The Supreme Court held that, because the individual mandate is unenforceable, the plaintiffs lacked standing because they had not shown a past or future injury that is fairly traceable. Notably, the Supreme Court did not rule on the constitutionality of the ACA.
California v. Texas, 593 U.S. (2021) is available here.