BANFF, Canada — President Donald Trump and Ukrainian counterpart Volodymyr Zelensky were supposed to meet on the sidelines of the Group of Seven leaders’ summit in Canada, one day after Trump complained that Russia should never have been removed from the organization.

But Trump’s premature departure from the summit on Monday, citing Israel‘s war with Iran in the Middle East, upended those plans and Zelensky’s latest opportunity to plead his country’s case to the president, proving Zelensky’s challenge is not only Trump himself but his many competing priorities.