If you want a more anti-war, civil-liberties-based liberalism than you have to argue for it, work with activists to build up grass-roots support for those policies, and vote for local and state candidates who support those ideas.
If you're running for president, you generally follow two basic courses of action to fund your campaign: either work your connections at the grass-roots level, or dive straight in to the rivers of cash that flow through places like Manhattan and Los Angeles.
Real school choice, with real grass-roots, bottom-up reform means that a community of people who care about their public goods deeply want to work to make those goods better.