[u320]

The entire purpose of joining NATO is to defend against russian imperialism (Something Sweden has a ton experience with, for hundreds of years) Always has been. There is not much point in joining if you exclude that bit.

[Terr_]

Certainly the main purpose, but I think over the last 70+ years there are some other benefits to members.

For example, fostering trade of military goods and technologies between members (especially for the USA as a major exporter) and smoothing out their national budgeting since it's kind of like buying insurance.