British Prime Minister Keir Starmer (R) greets Ukrainian President Volodymyr Zelensky (L) on Thursday as he arrived at Blenheim Palace, nine miles north of Oxford, for a European Political Community summit. Pool photo by Chris Ratcliffe/EPA-EFE LONDON, July 18 (UPI) -- Ukrainian President Volodymyr Zelensky told a summit of European leaders near Oxford, England, on Thursday that Russian aggression against his country had failed in its goal to divide the family of Europe -- but warned against any backsliding. "We have maintained unity in Europe and are acting together, which means that [Russian President Vladimir] Putin has missed his primary...