The goal of ending war, if presented in a non-partisan way, should have enormous appeal. It should attract Americans on the left and right, liberals and fiscal conservatives, business folk and people of faith. Given recent protests at Google and other companies, I bet many technology workers would support an antiwar movement. And imagine what would happen if those for whom the Bible serves as sacred text started taking its prohibition against killing seriously!
Even the most just wars are immoral, because they invariably kill the innocent, including children. Wars are also terribly wasteful. If we cut the U.S. military budget in half, it would still be bigger than that of Russia and China combined. And think of the resources freed for addressing problems like health care, criminal justice, education and climate change! As other activists point out, defense cutbacks could help pay for the Green New Deal, your exciting program for countering global warming and other threats to the environment.