Tom Tugendhat is the chairman of the UK's Foreign Affairs Select Committee and a Conservative member of the UK Parliament. Prior to his political career, he served in both Iraq and Afghanistan. The opinions in this article belong to the author.

(CNN) Every veteran remembers the first time they came under fire. That combination of adrenalin and fear makes combat so electric that it links you with every other generation who fought. That realization -- relief even -- that you weren't a coward, you didn't run and you did your duty.

Though he achieved many things -- including speaking out against waste in the US government -- that appeal to me as a Conservative, my respect for Arizona's representative's achievements in the US Senate isn't why I'm calling for him to be remembered at NATO. I'm thinking about the future and the lessons he can still teach.

John McCain was one of the first to spot the changes coming to Europe. He realized that though the Cold War was over, a new mafia state was rising and spreading corruption as poisonous as the communist ideology of its predecessors.

When he looked at the eyes of President Putin, McCain said he only saw three letters : KGB.

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And he should know: he'd been tortured by their fellow travelers in Hanoi, Vietnam. That's why he saw the value in our alliance.

NATO isn't just about protecting those countries of eastern Europe that border Russia, it's about protecting us all.

For the UK -- and even more for the US -- it's about making sure our borders are thousands of miles from our coasts, giving our people strategic depth few nations could even dream of. That's why great leaders of the past -- including NATO's first military commander general, then President Eisenhower -- invested so much in ensuring the alliance worked.

Today, our alliance is under threat. Too many of our fellow members take it for granted and haven't paid their dues. That means countries like the UK and US are carrying more than their fair share of the burden.

That's not right -- especially at a time when the borders of Europe are being changed by force for the first time since World War II.

Russia's invasion of Ukraine and Georgia -- both strongly condemned by McCain --point to a possible future if we forget that defense matters, and that soldiers buy peace.

He reminded us that we could write our own story. If we pooled our commitments and shared duty, our nations are strengthened, not weakened.

That was never more clear than on 9/11. For the first and only time in NATO's history the alliance unanimously agreed Article 5 of the NATO treaty that links us all together -- an attack on one is an attack on all -- and NATO went to war. Not in defense of a smaller state, but the strongest.

That's why this tribute to Sen. McCain isn't about him, it's about the ideas of liberty he spent a lifetime fighting for.