While meeting with NATO leaders in Brussels, American Secretary of Defense James Mattis once again called on member nations to fulfill their financial obligations to the alliance, warning that a failure to do so could result in America shifting its level of commitment to the organization.

“I owe it to you all to give you clarity on the political reality in the United States, and to state the fair demand from my country’s people in concrete terms,” Mattis said.

“America will meet its responsibilities, but if your nations do not want to see America moderate its commitment to the alliance, each of your capitals needs to show its support for our common defense.”

NATO is composed of twenty-eight member nations, each of which is obligated by its charter to devote two percent of their gross domestic product to defense spending.  However, only five of the twenty-eight have been meeting those requirements, with the United States footing the overwhelming majority of the bill.  Presidents Obama and Trump have both made critical statements regarding NATO members failing to meet this obligation in the past, but concerns were heightened when Trump suggested that the United States’ commitment to NATO may waiver under his administration if other nations don’t start taking their parts of the deal more seriously.