I have just written this new article for Slate.  It begins:

The Supreme Court will soon decide whether to reverse a federal court ruling requiring the state of Ohio to let its counties decide whether to permit early voting during the weekend before Election Day. With the presidential race tight in Ohio, and the presidency potentially turning on the state’s electoral votes, the court’s decision could help determine who will win the White House. While the Obama campaign has a strong policy argument for the extension of early voting to include this final weekend, its constitutional claim is a major stretch.