Why the US isn't scared of Russia's S-400

ussia’s S-400 Triumf, often referred to as the SA-21 Growler within NATO circles, is widely touted as one of — if not the — most capable air defense systems in the world. With the ability to leverage a variety of missiles to engage different air threats, an engagement range of nearly 250 miles, and widely praised counter-stealth capabilities, the S-400 has gained a reputation as one of the few systems capable of countering America’s air-dominance approach to warfare.