Republicans are teeing up a legal challenge before three judges appointed by Donald Trump in deep-red Mississippi that could boost similar lawsuits in more competitive states. The Republican National Committee and other plaintiffs argue that Mississippi is violating federal law by counting mail ballots that arrive within five days after Election Day, which resembles statutes on the books in nearly two dozen other states and jurisdictions. A ruling in their favor could help them in similar cases elsewhere, reported CNN. “It’s a clever strategy,” said Derek Muller, a Notre Dame Law School profes…