Russian President Vladimir Putin’s operational pause has more to do with the effectiveness of the High Mobility Artillery Rocket System, or HIMARS, than resting his troops. They don’t have a counter. The battlefield is no longer entirely tilted in Russia’s favor.

Surprise is bad in combat. Putin and his generals were led to believe the much-vaunted Russian S-400 air defense system would provide sufficient protection against HIMARS. It has proven ineffective, and heads will likely roll within the Russian defense industry.