On July 31, the Colorado Republican Party filed a federal lawsuit against the 2016 law that requires the party to let independent voters vote in its primaries, unless the party state convention votes by a 3/4ths majority to close the primary that year. Colorado Republican Party v Griswold, 1:23cv-1948. The case is assigned to U.S. District Court Judge Robert E. Blackburn, a Bush Jr appointee. Here is the 22-page Complaint.
Whether parties have a constitutional right to exclude independents from their primaries is an open issue. Republican Party lawsuits on this subject have won in Idaho, but have lost in South Carolina and Virginia. The U.S. Supreme Court already ruled in Tashjian v Republican Party of Connecticut that parties have a right to demand that independents be allowed to vote in its primaries. And in California Democratic Party v Jones, it ruled that parties have a right to exclude members of other parties from their primaries. Thanks to Mike McCorkle for the news.