Along the campaign trail, Donald Trump said a number of things that concerned prominent Democrats and foreign leaders. Some of these things can be chalked up to campaign rhetoric, but few of these remarks made the heads of foreign governments wiggle uncomfortably in their chairs more than his stance on NATO.

In what would become a controversial series of statements made to the New York Times during his campaign, President-elect Trump explained that, under his administration, the military might of the United States may not be forthcoming to the other members of the NATO alliance in their times of need. Trump went on to explain that, while the United States has always been one of the primary financiers of the organization, not all member nations are contributing as they should be.

Among foreign leaders and American Democrats, these statements were seen as sacrilege. The North Atlantic Treaty Organization dates back to 1949, when its founding members chose to combine their political and military strengths to present a unified front against Soviet (read: communist) expansion, prevent the revival of nationalist militarism the likes of which the world encountered in both world wars, and encourage the political integration of European and North American nations. In effect, the organization was intended to prevent a third world war, in large part by rebuking what was then seen as the most likely candidate to start it: the Soviet Union.

So why on Earth would Donald Trump take such a controversial stance on such an important and historically significant organization? In the face of a new era of Russian posturing, Chinese naval expansion, North Korean nuclear weapons, and wars in multiple theaters, what could possibly lead America’s president-on-standby to consider weakening alliances with other nations? The world seems primed for conflict and sparks in Syria, the South China Sea, and Iraq could all feasibly light the fuse. Why, now more than ever, would we choose to stop honoring the agreements we’ve made with friendly nations?

Well, in part because those nations already stopped honoring them.

In much of the media, Trump’s statements were intentionally conveyed in a manner that made his stance seem like a protection racket run by mobsters. Trump said the U.S., under his administration, would only intervene on behalf of other NATO nations if those nations had “fulfilled their obligations to us.” This statement was percieved to mean that Trump would only protect our NATO allies if those countries were willing to pay for the service. As a candidate that was already depicted in the media as a cold-blooded shark-like businessman, many were disgusted at the concept that we’d charge our sister nations “protection money,” but in truth, that was never Trump’s stance.

Article 5 of the Washington Treaty is seen as the core, guiding principle behind NATO as an organization. It states plainly that an attack against one ally is seen as an attack against every member of the alliance. NATO invoked this article after the September 11th, 2001 terrorist attacks on the United States, providing immediate military and political support to America in the wake of the disaster. It’s important to note, however, that the level of the support each member nation is required to provide is not laid out specifically in the charter, only that each nation must take “action as it deems necessary, including the use of armed force.”

Opponents of Trump’s position cite this cornerstone principle of the alliance as damning evidence that he either doesn’t understand the nature of the organization or has so little respect for NATO and its members that he believes he can dirty-business his way into granting America increased negotiation leverage. Neither are true (at least entirely). In truth, there’s another part of NATO’s charter that has been ignored by a number of politicians in recent years, dating back to well before Trump was even taken seriously as a candidate: the GDP requirement for all of NATO’s members.