When I arrived in Afghanistan in 2011 for the first time, I proudly displayed several patches on my shoulders. One was the flag of the United States, the country I love so much. Another was the 10th Mountain Division insignia, representing the unit with which I had been deployed. But there was also one more: the Isaf patch, signifying participation in Nato’s International Security Assistance Force.

So, when President-elect Donald Trump claimed in a recent interview that Nato is obsolete in part because it “didn’t deal with terrorism,” I was dismayed. Trump’s assertion is patently untrue, and it disrespects the efforts that fellow Nato members have made to combat this threat.

In case Trump needs a history lesson, the North Atlantic Treaty, signed in 1949, including article five, provides that Nato countries will collectively defend each other in the event of armed attack on any member.

Through the Cold War, Article 5 never had to be invoked, which is a testament to the organization’s deterrent effect on adversaries. But following the 9/11 attacks on the United States conducted by al-Qaida – who had been harbored by the Taliban in Afghanistan – Nato invoked Article 5 for the first time ever, specifically to deal with terrorism.

Whether Nato’s campaign against terrorism has been effective is a fair question. Some might argue that al-Qaida, which has been unable to conduct another attack on the scale of 9/11, has largely been denied safe haven in Afghanistan, and that terrorism does not present an existential threat.

On the other hand, some might argue that al-Qaida’s persistence and a resurging Taliban provide evidence that Nato has not succeeded in its task. One could also argue that Nato should be more involved in countering Islamic State (Isis) in Iraq and Syria, because of the threat the organization projects into Europe. However, these considerations should not obscure the undoubted fact that Nato has taken concrete steps to deal with terrorism since 9/11.

In addition, despite what some may think, the burden of the Nato mission has fallen on the shoulders not only of the US. Consider the fatalities suffered by Nato members in Afghanistan. If we use the methodology of a 2010 analysis that looked at fatalities-per-population and apply it again today, we can see the tiny country of Denmark ranks higher than the United States, which comes in second.

It therefore appears that Trump was shooting from the hip, blatantly disregarding history and disrespecting Nato allies along the way. But should we be surprised?

When it comes to fighting terrorism, Trump is clueless. This is the same man, after all, who ludicrously proposed that Mosul could and should be captured from Isis in a surprise attack. According to outgoing CIA Director John Brennan, this kind of careless spontaneity is “not something that protects national security interests.” Will he ever learn?

