I’m writing this editorial about a week ahead of the Paris Air Show. And I’m thinking, what a shame that allies can’t get on the same page.

And I say that not because of any rhetoric about European defense investments or so-called America First. (That doesn’t help, obviously.) I more am referring to the discourse between regions, between alliances.

The European Union is touting merits of its efforts to fund members in defense efforts, after NATO criticisms. The U.S. and the United Kingdom are independently objecting to not having access to those funds. The U.S. is funding efforts in Eastern Europe to cut off dependence on Russian systems, despite analysts predicting a negative impact for European manufacturers. And while the U.S. is taking a firmer stance against China, European allies are skeptical.

None of these efforts or philosophies are ill-intentioned. I wrote in a different editorial in fact that the United States’ European Recapitalization Incentive Program is actually a pretty innovative concept, if executed carefully, and I’d say the same about the EU’s European Defence Fund. And China is a complicated adversary for everyone.

But we are seeing more natural tensions emerge as countries focus on domestic or regional priorities — even when those priorities don’t necessarily meld with pre-defined missions of trans-Atlantic alliances.

Why now? It actually makes sense when you consider that the threats are more distinct than ever. To one NATO member, particularly those along the eastern flank, Russia is a volatile neighbor; for them, the potential for insurgency requires investment in border security and troop presence and ongoing surveilliance. To other NATO members, including the U.S. and the U.K., Russia is a near-peer competitor and a burden. Moscow certainly remains the focus of security investments, but the tactics to combat the threat are quite different. Similar statements could be said about the degree of the threat posed by Iran, North Korea and China.

No country has endless funds. Each country will prioritize, and allies may or may not agree with the strategy. By the same token, all countries want to see defense investments filter into the coffers of their own industrial base, and yes — that will naturally be at the expense of others.

I asked Jorge Domecq, the chief executive of the EU’s European Defence Agency, why its current efforts to bolster defense investments among its members couldn’t have happened under NATO. His answer was quite simple: in NATO, the mission is collective defense, but “a common defense” is not possible.

That seems fair to me. And actually, a similar argument could be made by others for their own efforts to bolster domestic capabilities, even if not perfectly aligned to the universal mission: It’s what’s best for their own security.

None of this is to say that NATO or the U.S. independently or the EU can’t or won’t move forward in a productive way. But growing pains are happening, and the relationships will change.

As I wrote in December: We enter 2019 with what seems to be more emboldened allies. Individual countries were investing more in defense — less to appease the United States and more to close their own gaps in domestic security. Such investments signaled then an evolving view on NATO, from a security blanket of sorts, particularly for smaller member states, to an alliance that derives its strength from the sum of its parts.

And now we see the next stage of that transition, and aspects of it are uncomfortable for some. But change — and progress — is never easy.