The Globe and Mail reports in its Monday edition that Ottawa's threat last week to reconsider the purchase of new military jets from Boeing after it called for a trade review of Bombardier was a classic tit-for-tat move. Guest columnist Tom Koch writes that too, is B.C. Premier Christy Clark's request to Ottawa to bar coal exports from B.C. in retaliation for the current softwood-lumber battle. Note that bluster and shaming are not part of the program. Threats score no points. There is no advantage to referring to a prior history of shared hardships or proclamations of long-term friendship. The rules are simple: proportional response and, when the opportunity arises, co-operation. Tit-for-tat is not a zero-sum game. Beginning with co-operation, it assumes the best outcome will probably be less than everything. Nobody gets everything, but all get enough to maintain a peaceful equilibrium. It may be a game strategy, but as we are discovering, it is one with real-world applications. In the current climate of escalating political conflicts it is certainly worth trying. Politeness is too often mistaken for weakness by the bullies of the world. With tit-for-tat, nice guys don't need to finish last.