Britain's double "Brexit" - FT.com The full price of the misbegotten invasion and occupation of Iraq is only now becoming apparent. As life is rarely fair, it has also been the case over the years that much of the bill is being paid not by those who launched the Mesopotamian misadventure, but by others. The UK government's decision to seek authorisation for action in Syria from parliament is a direct consequence of the Iraq war, as has been the shift of much of the British political establishment - largely but not only in the Labour party - towards positions reminiscent of those in Germany at the time of the Libyan campaign. These are the developments that led to the stunning vote by MPs rejecting British participation in a possible military strike on Syria. The consequences of that decision are strategically substantial. IN Opinion The immediate effect is something akin to a double "Brexit"; Britain is turning its back simultaneously on the US and on France. Astonishment is a mild word to describe reactions to the vote in Washington and Paris. The already dim view taken by an Asia-centric US of the role of Europe in America's grand strategy will darken further, because the UK is rightly seen as part of Europe despite the best efforts of some in London to dispel that impression. Britain's opt-out will be taken as one further step away from strategic relevance and seriousness for Europe. The "tough love" that characterises US attitudes towards its European Nato partners will become somewhat tougher and rather less loving. As crisis-ridden Europe's defence spending decreases and its strategic exposure to a chaotic Middle East and an assertive Russia increases, this is not a welcome development. The effects in France are different but equally disturbing. Despite the jokes concerning the "entente frugale" between Paris and London, the fact is that the 2010 Lancaster House treaties have brought our defence co-operation to an unprecedented level, between our armed forces and our defence industries, and most strikingly in the nuclear arena. People on both sides of the Channel will work overtime to salvage that relationship. However, it has been seriously damaged because one of its basic assumptions, that of systematic joint purpose, has now been proved wrong. Key elements of the international system will also feel the repercussions of the London vote. Post-cold war efforts to build an international framework for the use of force to protect civilian populations had already been badly hurt by Russia and China's double veto in the UN Security Council on the Syrian conflict. With Britain's decision, even operations conducted by international coalitions - as was the case during the Kosovo air war - may also be politically out of reach. France may have reasons to be proud of its ability and willingness to face the tyrant in Damascus, but the French know full well that acting as one of a kind alongside the US does not constitute a multilateral operation. In other words, the law of the jungle has a bright future in a world of perpetrators (some), bystanders (a growing majority) and an increasingly isolated and challenged American superpower. This, of course, assumes that the US will act in Syria. The catastrophe would be complete if Britain's choice hastened an American decision to refrain from striking. America's strategic credit, after having so clearly drawn a red line (which even Russia had approved of in 2012), would sink to a new low. The refusal to act would prompt risk-taking by the impatient, draw scorn from the rising powers, and lead to hedging strategies from its allies. Most ominously, a failure to provide a brutal and effective response to Mr Assad's use of nerve gas would undermine an already fragile non-proliferation regime. The use of chemical weapons is outlawed, universally and unambiguously. Allowing that level of transgression to go unpunished would force a rethink about the acquisition and use of chemical weapons and other weapons of mass destruction by many countries, particularly those with little regard for the sanctity of human life. The fact that Britain entered the wrong war at the wrong time 10 years ago does not mean weapons of mass destruction and their use - as has been the case in Damascus - are not real and may have to be met with lethal force. Presumably, an American-French strike would fulfil the immediate goal of restoring deterrence vis a vis the use of chemical weapons. However, such an operation would hardly be seen as a politically broad-based venture. In the long run, the success of non-proliferation policies must rest on multilateral agreement and action. The vote in the House of Commons has moved us further away from satisfying that requirement. The writer is special adviser at the Fondation pour la Recherche Stratégique