Recent U.S. funding cuts and freezes to humanitarian demining efforts threaten to reverse decades of progress in clearing landmines and unexploded ordnance worldwide, destabilizing organizations that rely on this support and forcing massive layoffs of demining staff in over 20 countries. The uncertainty and reductions in aid risk increasing civilian casualties, prolonging dangerous contamination, and undermining U.S. humanitarian, security, and geopolitical interests — especially in countries affected by past American-led wars. With other donors unable to fill the gap, the loss of U.S. leadership in mine action will have lasting, deadly consequences.