This is one of those questions to which the answer depends entirely on who you ask. You'll find Saints and Church Fathers on both sides of the equation; some were pacifists to the fullest extent of the word, others believed the Church and State should work together to physically fight against not just enemies of the nations, but heretics as well. The Byzantine Empire, which was Christian from start to finish, fought against its enemies as much - and as violently - as any other nation of its time. You'll find St. Augustine writing his theory of Just War, and other Saints saying never to fight. You'll find Saints saying that we have no homeland on Earth, and St. Philaret of Moscow saying that enemies of the nation should be destroyed.I struggle with this question: should we do nothing as Orthodox ? Or should we fight ?
It's one of those things where you have to search the Word and your own conscience, thinking carefully through your approach to each situation. Personally I agree with St. Augustine's Just War: you exhaust every possible means of solving the problem peacefully, but if you have no other options you commit the smallest amount of violence necessary in order to restore peace. Obviously this is done only in defense, never as the aggressor in any situation. I also think it's crucial to apply the theory differently depending on who is being attacked and why; if you're being attacked for your faith, as an individual, then the martyrs have made the answer clear. If your family or community are being attacked, then personally I think it's fine to do whatever you have to. There is certainly no virtue in cowardice, and I reject the fake meekness espoused by cowards who think the righteous thing to do is allow their own family and friends to be killed so as not to be "violent" or "bad." They are condemning others to death in order to make themselves feel virtuous, which is despicable to any honorable man.
The Russian Orthodox political philosopher Ivan Ilyn wrote a book called "On Resistance To Evil By Force." He has a pretty good breakdown of the topic, though admittedly I'm only partway through the book. You might find some helpful answers in it.