Where a military or diplomatic victory has not worked in six months of war, the US’s new sanctions on Iran appear to be an attempt to accomplish what “military force has so far failed to achieve”, says Sina Toossi, a senior fellow at the Center for International Policy. “But Tehran is answering that zero-sum approach with one of its own,” he said, adding that Iran will first try to dissuade neighbouring states from joining the US campaign, but that participation could be treated as an “act of war”.