Gita certainly does not advocate war

In his famous Essays on the Gita, Sri Aurobindo summed up the whole problem in these words: "We will use only soul-force and never destroy by war or any even defensive employment of physical violence."

Good, though until soul-force is effective, the Asuric force in men and nations tramples down, breaks, slaughters, burns, pollutes, as we see it doing today, but then at its ease and unhindered, and you have perhaps caused as much destruction of life by your abstinence as others by resort to violence. Strength founded on the Truth and the dharmic use of force are thus the Gita’s answer to pacifism and non-violence. Rooted in the ancient Indian genius, this third way can only be practised by those who have risen above egoism, above asuric ambition or greed. The Gita certainly does not advocate war; what it advocates is the active and selfless defence of dharma. If sincerely followed, its teaching could have altered the course of human history. It can yet alter the course of Indian history."

The Gita is, in Sri Aurobindo’s words, “our chief national heritage, our hope for the future." (source: The Gita in Today’s World - by Michel Danino - bharatvani.org). Also refer to Gita Supersite.