The war in Ukraine has sent shockwaves through the European Union, exacerbating existing fault lines around energy, climate, fiscal rules and foreign and security policy. The unprecedented sanctions against Russia and the wider response to its invasion have further divided the bloc, with Eastern states pressing for stronger action, including a gas and oil embargo, and Western members, led by Germany, arguing for a more cautious approach. Whether the EU can keep a united front in response to Russian aggression will also depend in large part on the outcome of this weekend’s runoff in the French presidential election. A President…