The geopolitical impacts of Russia's war on Ukraine rippled further this week, with Sweden and Finland's requests to join NATO—potentially breaking decades of neutrality for those countries and adding a complex new layer to Europe's political and defense landscape.

"This is a hugely significant development, and it simply would not be happening if Putin had not invaded Ukraine," said Mary Elise Sarotte, an international relations historian at the Johns Hopkins School of Advanced International Studies, during a virtual event Tuesday. "It's significant politically, it's hugely significant militarily, and it's significant in terms of the message it sends."