Thesis Pacifism is the most consistent ethics of war, not a refusal to have one
Where it stands
I grew up among Jain neighbours in Hyderabad and came to Gandhi through them. Gandhi credited Tolstoy's The Kingdom of God Is Within You (1894) with a large influence on him, so the pacifist line I have absorbed runs from Mahavira through Tolstoy to Gandhi, three quite different routes to one refusal.
People usually treat pacifism as the position that has given up on ethics of war, as if it simply declines to answer the hard question. I want to argue the opposite.
Take the just war criteria seriously: just cause, legitimate authority, right intention, proportionality, reasonable prospect of success, last resort, discrimination, necessity. Apply them honestly to the wars of the last few centuries. Almost none pass. That conclusion is called contingent pacifism: just war is possible in principle and almost never achieved in practice. My claim is that this is where just war theory leads when its own conditions are taken seriously, and that full pacifism simply draws the conclusion without the loophole.
There is also an empirical point. Research such as Chenoweth and Stephan's Why Civil Resistance Works (2011) argued that nonviolent campaigns have succeeded more often than people assume, although I know the findings are debated.
I am not saying pacifism is easy. I am saying it is the consistent position, and that it asks a great deal more than it is usually credited with.