Snarled supply chains that helped fuel red-hot inflation are slowly disentangling, offering hope for relief for cash-strapped consumers. But the U.S. faces geopolitical tensions, a shortage of truck drivers and a potential railroad strike that all endanger recent progress. The New York Federal Reserve’s global supply chain pressure index soared to an all-time high in December 2021 and remained elevated for much of this year before plummeting in recent months, reaching its lowest level in nearly two years last month. The coronavirus pandemic initially shut down major economies, leaving companies understaffed and unprepared for the explosion of demand that followed,...