> If they are attacked we have to defend them and they know it. They would contribute a relatively insignificant amount if we were ever attacked.

If? In the entire history of NATO, the mutual defense provisions of the treaty have been invoked exactly once, and that in response to an attack on the US, and the non-US NATO contributions were not insignificant.

>the mutual defense provisions of the treaty have been invoked exactly once

that's the point

Sure, deterrence is the point of the treaty, but the claim upthread was about the significance of contributions that would be made in the event of an attack, a claim which contradicts the facts of the time when an attack resulting in the mutual defense provisions being invoked actually occurred.

> They would contribute a relatively insignificant amount if we were ever attacked

Many Europeans gave their lives in Afghanistan, responding to an attack on the U.S., and also in Iraq on a fools errand. The U.S. is the predominant power, but that doesn't make others insignificant.

The fact that we spend too much by an order of magnitude or two doesn't mean the rest of the world is dependent on us. We don't spend this much because it's the only way to make the world safe. We spend this much because every Congressman has a some part of a defense contractor in their district and they'd rather build billion dollar boondoggles that the military leadership explicitly doesn't want than vote to close the local plant.