On August 2, the Iowa Libertarian Party filed a federal lawsuit against the March petition deadline for non-presidential independent candidate petitions, and the non-presidential petition deadline for the nominees of unqualified parties. Iowa Libertarian Party v Pate, s.d., 4:19cv-241.
The Iowa deadline had been in mid-August ever since 1953, until 2019, when the legislature moved it to mid-March. Before 1953 the deadline had been in late September, and before that, in early October. So the 2019 change was drastic.
The case is assigned to U.S. District Court Judge Stephanie M. Rose, an Obama appointee. Here is the Complaint.