Anarchism

I have been reading a book about the history of Israel. One section was about people refusing to serve the army when Israel fought war in Libanon and Gaza because they didn't agree with cruelties the Israel army conducted/ accepted. It made me think about the other way around: What if your country is attacked and people are being called to service by the army, would an anarchist refuse out of principle?

Quite some anarchist reject the idea of a centralized army so an anarchist might refuse out of principle. On the other hand, your country is being attacked. You can argue that accepting service is accepted because it is different from invading another country because you now have to defend your own country.

What are your thoughts on this?