NATO is not guaranteed to last forever. One thing about coalitions that I learned after studying political and military history going back to about the Peloponnesian War: coalitions last about as long as they are politically useful to their members. Heck, Napoleon faced five different coalitions in 20 years time.
Would I rather see NATO survive? Yes. Warts and all, I think that the Transatlantic link matters.
But there needs to be a political reason, a compelling political reason, to keep any coalition together.
What is it?
Answer that question, and you have the answer on how to keep it together.
As ever, answers on a post card ...
But if NATO folds for whatever political reason, the EU and WEU need to be ready to stand up.
Are they?