A looming ruling by a federal judge in Manhattan poses a tricky credit-markets question: Can a hedge fund ever be justified in forcing a perfectly functional company into bankruptcy?

The company is Windstream Holdings (ticker: WIN), a network communications and cable operator in Little Rock, Ark. Windstream employs 14,000 people, and provides cable in 18 rural American states. For 20% of its areas of operation, Windstream is the only option.

Its...