EXPLAINER: Why Finland, Sweden joining NATO will be big deal


              FILE- NATO naval mine countermeasure vessels berth in Turku, Finland, during the international Northern Coasts 2014 (NOCO14) military exercise on Aug. 29, 2014. Finland appears on the cusp of joining NATO. Sweden could follow suit. By year's end, they could stand among the alliance's ranks. Russia's war in Ukraine has provoked a public about face on membership in the two Nordic countries. They are already NATO's closest partners, but should Russia respond to their membership moves they might soon need the organization's military support. (Roni Lehti/Lehtikuva via AP)
            
              FILE - President Joe Biden is greeted by NATO Secretary General Jens Stoltenberg as he arrives for meetings with NATO allies about the Russian invasion of Ukraine, on March 24, 2022, in Brussels. Finland appears on the cusp of joining NATO. Sweden could follow suit. By year's end, they could stand among the alliance's ranks. Russia's war in Ukraine has provoked a public about face on membership in the two Nordic countries. They are already NATO's closest partners, but should Russia respond to their membership moves they might soon need the organization's military support. (AP Photo/Evan Vucci, File)
            
              A moment of the military exercise SWENEX at the Marine regiment in Berga, Sweden, Oct. 27, 2021. Finland appears on the cusp of joining NATO. Sweden could follow suit. By year's end, they could stand among the alliance's ranks. Russia's war in Ukraine has provoked a public about face on membership in the two Nordic countries. They are already NATO's closest partners, but should Russia respond to their membership moves they might soon need the organization's military support. (Fredrik Sandberg/TT via AP)
            
              FILE - In this photo provided by the Swedish Armed Forces on Aug. 25, 2020, troops prepare in the Baltic Sea region. Finland appears on the cusp of joining NATO. Sweden could follow suit. By year's end, they could stand among the alliance's ranks. Russia's war in Ukraine has provoked a public about face on membership in the two Nordic countries. They are already NATO's closest partners, but should Russia respond to their membership moves they might soon need the organization's military support. (Joel Thungren/Swedish Armed Forces/TT via AP, File)
            
              A Leopard battle tank of the Armoured Brigade is seen during the Army mechanised exercise Arrow 22 exercise at the Niinisalo garrison in Kankaanp'', Western Finland, on May 4, 2022. Finland appears on the cusp of joining NATO. Sweden could follow suit. By year's end, they could stand among the alliance's ranks. Russia's war in Ukraine has provoked a public about face on membership in the two Nordic countries. They are already NATO's closest partners, but should Russia respond to their membership moves they might soon need the organization's military support. (Heikki Saukkomaa/Lehtikuva via AP)
            
              Reservists of the Karelia Brigade shoot with live rounds during the Etel'-Karjala 22 (South Karelia 22) local defence exercise in Taipalsaari, south-eastern Finland, on March 9, 2022.  Finland appears on the cusp of joining NATO. Sweden could follow suit. By year's end, they could stand among the alliance's ranks. Russia's war in Ukraine has provoked a public about face on membership in the two Nordic countries. They are already NATO's closest partners, but should Russia respond to their membership moves they might soon need the organization's military support. (Lauri Heno/Lehtikuva via AP)