With no significant breakthrough after six weeks, it is worth asking whether Ukraine’s counter-offensive can ever succeed, for it certainly doesn’t look to be succeeding now. Compare the glacial but costly progress today to the lightning victories at Kharkiv and Kherson last autumn. Back then Kyiv’s forces were advancing against a withdrawing enemy that was pulling back to redeploy troops, trading space for time. Having now built up their forces through mobilisation and dug extensive defence lines, this time the Russians aren’t going anywhere. That has left Ukraine with one option: launching frontal attacks against heavily defended positions, almost akin...