European leaders will face a historic decision at their next summit in December. After years of prevarication, they must decide whether the EU is finally ready to accept new members. Geopolitical shocks such as the war in Ukraine, but also the growing prospect of a long-term rivalry with China, have precipitated this moment of truth. Yet the real dilemma lies elsewhere. As the EU charts a path for the accession of new countries including Ukraine, Moldova and Bosnia and Herzegovina, the question of Turkey looms large.