A new, potentially final, round of Brexit talks start on Monday, with a breakthrough still proving elusive. However, even if a deal is agreed before the October deadline, a further major challenge could come from the ratification process. Given that negotiations remain on a knife-edge, the ratification phase has not yet been explored in great detail by much of the media, despite the fact that it is a key, distinctive stage in what is the most complex peace-time dialogue ever undertaken by the two sides. This is a significant oversight. For, while the Brexit withdrawal deal, which facilitated the UK’s departure from the EU in January, was ultimately ratified at relatively fast speed, this may not necessarily be the case with any forthcoming agreement on the future EU-UK trade relationship. The difficult nature of this ratification can be highlighted by looking at the troubled approval process for the Canada-EU Comprehensive Economic and Trade Agreement (CETA). Some have pointed to this deal, which saw a near breakdown of negotiations in 2016, as an aspirational model for future UK-EU relations. EU-Canada turbulence came to the boil in October that year, when Wallonia — one of Belgium’s six legislatures — indicated to Canada that its opposition to key provisions were “red lines.” This opposition delayed, and nearly derailed, the Belgian government’s approval. While Wallonia’s concerns were ultimately smoothed over by Ottawa and Brussels, the episode underlined the complexity of Europe’s approval of trade deals. Unlike the Brexit withdrawal deal that facilitated the UK’s departure from the EU, big trade agreements like CETA need approval from about 40 national and regional parliaments across the continent before they can be implemented in full. Moreover, any deal agreed between the UK and the EU will need the approval of the European Parliament in Brussels and possibly the European Court of Justice (ECJ) too. It is often forgotten that, in the early 1990s, the ECJ struck down some early arrangements for European Economic Area-EU relations, ruling that they breached the EU’s treaties. UK and EU politicians may, therefore, face considerable constraints in creating a new post-Brexit UK-EU legal architecture. With ratification likely to take weeks, if not months, this is why Oct. 15 has been set as an unofficial deadline for a Brexit breakthrough by UK Prime Minister Boris Johnson. This is immediately before a European Council meeting of the 27 European presidents and prime ministers, who would also need to give their blessing to any deal that emerges. An agreement before Oct. 15 is still possible given that, amid the pessimistic mood music of recent talks, bilateral differences are narrowing and both sides have made some key concessions. This progress means there may now be the “landing zone” for a deal, albeit one that is far less deep and comprehensive than was talked about only a few months ago. Big trade agreements need approval from about 40 national and regional parliaments across the continent. Andrew Hammond If such a “thin” deal is agreed, but there is a failure to secure ratification before Dec. 31, this outcome would be the same as the absence of an accord: Namely, a disorderly no-deal Brexit raising its head again. This underlines that, with deadlines fast approaching, the final form of the UK’s departure from the EU is still far from clear. Multiple scenarios are possible, ranging from a disorderly no-deal exit through to a breakthrough and a modest trade deal being agreed that might be built upon in the years to come. For all that the UK’s withdrawal from the EU in January was a seminal moment in post-war history, Brexit is far from being “done,” despite what Johnson has said. The stakes in play therefore remain huge and historic in the coming weeks, not just for the UK, but also the EU, which could also be badly damaged by a no-deal scenario. Delivering a smoother departure now needs clear, coherent and careful strategy and thinking on all sides so that London, Brussels and the EU-27 can move toward a new constructive partnership that can hopefully bring significant benefits for both at a time of global geopolitical and economic flux. Andrew Hammond is an Associate at LSE IDEAS at the London School of Economics. Disclaimer: Views expressed by writers in this section are their own and do not necessarily reflect Arab News" point-of-view