Trump and his anti-American supporters are complaining because the DOJ has sued Virginia to enforce a Federal voter law that prohibits voter roll cleanups less than 90 days before an election.
For some bizarre reason, the press is covering this "issue" as though it were something other than the simple enforcement of crystal-clear federal law. It is not.
DOJ Press Release: https://www.justice.gov/opa/pr/justice-department-sues-virginia-violating-federal-laws-prohibition-systematic-efforts
Read 52 U.S. Code § 20507(c)(2)(A) here : https://www.law.cornell.edu/uscode/text/52/20507