After a decade of dramatic ups and downs, 2020 was supposed to be a climax year for U.S. wind farm construction. Instead, with the coronavirus pandemic rattling supply chains and thinning workforces, things could get messy for an industry that should be taking a victory lap. Developers are poring over force majeure provisions in their contracts. Investors are nervous. Without political relief, projects could get canceled outright, industry figures say — and relief in Washington, D.C. looks anything but certain. Every industry has been affected by the outbreak and its economic shock.