"We will look back on war someday like we did on slavery"
Yes. And withholding taxes, though admirable, is not going to solve the problem. The problem is the state itself; inevitably it looks to its own health, which is war. Not paying taxes is a start, though. The problem is that only people with no assets can realistically use such a strategy. The rest of us, with real jobs and real assets, will have to work against war in less punishable ways.