Most of Europe doesn't act like us or behave like us and are pretty "secure" from a national security perspective.
The only power that really matters is economic power and, honestly, military strength doesn't really help with that past the point you are roughly equal to everyone else.
Any country in the world would love to be in the position of security that the US occupies. Any one.
Why shouldn't we do everything we can to hold on to that treasure we have?