FREDERICKSBURG, Va. — Attorneys for L. Douglas Wilder have a week to respond to the city of Fredericksburg’s attempt to sell 38 acres where the former governor wants to build the National Slavery Museum.

The deadline is the latest back-and-forth over Wilder’s quest to build a museum telling the nation’s history of slavery. But first he must settle a large tax bill on the land and get fundraising back on track....