It was nearly a year ago that the White House announced that 130 countries expressed support for a 15 percent global minimum corporate tax at a meeting of the Organization for Economic Cooperation and Development (OECD). Now Poland is the lone holdout to the European Union unanimously adopting the agreement, after Sweden, Estonia and Malta withdrew their objections in April. In the United States, the agreement would need to be ratified by Congress, either as legislation or as a treaty.