In this article, we look at 21st-century warfare in the context of two great powers: Russia and America. Russian and American invasions and subsequent wars are evaluated in terms of why and how they are fought, legal and moral considerations, impact, outcomes, and consequences. The article examines similarities and differences in strategy and methods, expanding on the increasingly popular remote warfare. Finally, we assess the decisive role of science and technology in war, raising questions about the future of AI warfare.