In a 6-3 decision, SCOTUS rejected the notion that state legislatures have unlimited power to determine the rules for federal elections and draw partisan congressional maps without interference from state courts.
How much effect will this have on existing congressional maps and upcoming elections?
Paywalled. But is this the state legislature theory thing?
Yes. As mentioned upthread, a loss in this case would probably have spelled the end of democratic elections in this country for a generation or more.