This article explores how the 2022 Russian invasion of Ukraine has upended and reshaped Arctic security, institutions, and partnerships. With Arctic governance institutions that include Russia, such as the Arctic Council, on pause and scientific collaboration with Russia interrupted, the military dimension has overshadowed Arctic cooperation—while highlighting the traditional security risks of dependence on fossil fuels and distracting attention from other key Arctic issues such as climate change and the socioeconomic development of indigenous communities. Russia’s ambitions for agency as Arctic Council chair have been thwarted, and Moscow’s plans for economic development of the Russian Arctic and Northern Sea Route are in doubt. Although some regional cooperation continues through multilateral agreements, the path forward for dialogue on traditional and nontraditional security in the Arctic remains uncertain.