Iceland's Prime Minister Kristrún Frostadóttir and European Commission president Ursula von der Leyen are pictured in Brussels on Jan. 14, 2026. —Simon Wohlfahrt––Getty ImagesIceland is holding a long-awaited referendum on Aug. 29 to decide whether the country should resume accession negotiations with the European Union.The country initially applied for E.U. membership in 2009, but accession negotiations were halted upon a change in government i…